Han Li had lost his memory because Doctor Mo had forced him to cultivate the Eternal Spring Arts, causing him to go berserk. In the novel "A Record of a Mortal's Journey to Immortality", Han Li was taken in by Doctor Mo and taught the Eternal Youth Technique. However, Doctor Mo's goal was to use Han Li's body to cultivate the Eternal Spring Arts because he had already reached a bottleneck. During one of his cultivation sessions, Doctor Mo forcefully instilled the Eternal Spring Arts into Han Li's body, causing Han Li to go berserk and lose his memory. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!

In the "Mortal Cultivation Legend of the Immortal World Chapter", Han Li was a cultivator who obtained the ability to live forever in the process of cultivation. However, his memories were not as good as the others. In the later stages of the novel, Han Li discovered that he had lost 300 years of memory. This might be due to some indescribable things he experienced during his cultivation, causing his memories to be permanently sealed.
In the Scattered Star Seas, Han Li befriended a female cultivator named Ice Soul, and the two of them explored the cave abodes of ancient cultivators together. During the exploration, Han Li was injured by the ice soul and fell unconscious. When he woke up, he found that he had lost part of his memory. He did not know his background and past experiences. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
In the "Immortal World Chapter of Mortal Cultivation", it was the Truth Sect's Grand Elder Bao Hua who had plotted to make Han Li lose his memory. In order to obtain the Divine Sovereign Vase, the treasure flower had used an illusion technique to create a fake body of Han Li, allowing him to steal the Divine Sovereign Vase. When the fake body took the Divine Sovereign Vase, the treasure flower used the power of time laws to create a connection between the fake body and the Divine Sovereign Vase, causing Han Li to have the illusion that the Divine Sovereign Vase had been lost and to lose his previous memories. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
In the "Immortal World Chapter of Mortal Cultivation", Han Li had suffered a sneak attack from a Gold Devouring Immortal, causing his soul to be damaged and causing him to lose a portion of his memories. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
In the Immortal World chapter of the [A Record of a Mortal's Journey to Immortality], Han Li's memory loss was due to the Immortal Palace's emissary's scheme when he ascended to the True Immortal World. He was transported to the Black Wind Sea Region through the Ancient Devil Transfer Formation, causing a portion of his memory to be damaged. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
Han Li had lost his memory after being ambushed by the Bone Sage in the Scattered Star Seas. In order to obtain the Heavenvoid Cauldron, the cultivators of the Scattered Star Seas had besieged Han Li. During the chaotic battle, Han Li was ambushed by the Bone Sage. He had no choice but to detonate the Profound Heavenly Spirit-slayer Sword and the Inky Flood Dragon Banner before jumping into a spatial rift to escape. Later, he was saved by the Ice Soul Fairy at the bottom of the Fallen Star Sea, but he lost his previous memories. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
The 300 years of memory that Han Li had lost was related to Feng Tiandu's Element Separating Chains. In the "Mortal Cultivation Legend", Han Li was sealed by Feng Tiandu's Yuan Separating Chains during his trip to the Immortal World, causing him to lose 300 years of memory. In addition, Han Li had been struck by Tao Yu's Soul Destroying True Light, which was also one of the reasons why he had lost his memories. While waiting for the TV series, he could also click on the link below to read the classic original work of " The Legend of Mortal Cultivation "!
The reason why Han Li had lost 300 years of memories was because he had been struck by Tao Yu's Soul Destroying True Light. In his battle with Tao Yu, Tao Yu had used the Soul Extermination True Light as his last resort, causing Han Li to lose his memories. However, there was no mention of what had happened in the past 300 years, so there was no way to know the exact situation. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
In the "Mortal Cultivation Legend of the Immortal World", Han Li lost 300 years of memories because he was severely damaged by the Samsara Hall's time law attack. While waiting for the TV series, he could also click on the link below to read the classic original work of " The Legend of Mortal Cultivation "!
Han Li didn't mention the exact time he lost his memory. The search results mentioned the circumstances and reason for Han Li's amnesia, but they didn't specify the exact time when it happened. Thus, based on the information provided, I am unable to determine the exact time Han Li lost his memory. While waiting for the TV series, you can also click on the link below to read the classic original work of " A Record of a Mortal's Journey to Immortality "!
In the novel "Mortal Cultivation Legend", Han Li lost his memory in the Scattered Star Seas. In the Scattered Star Seas, Han Li had fought with a Form Synthesis cultivator. Due to the disparity in strength, Han Li had been knocked to the bottom of the sea, heavily injured and unconscious. He had lost part of his memory during his coma. When he woke up, he discovered that he was on a deserted island and his storage pouch was missing. As a result, he hunted for a living on the deserted island. Later, he was rescued by two cultivators. With the help of these two cultivators, Han Li recovered a portion of his memories. While waiting for the TV series, he could also click on the link below to read the classic original work of " The Legend of Mortal Cultivation "!