It could be a variety of things like toys, candies, or maybe a special surprise letter.
In the 28th episode of " Celebrating the Years," Fan Xian opened the box. Inside were three parts of a Barrett sniper rifle that Ye Qingmei had left for him. This sniper rifle was brought out from the temple by Ye Qingmei before she transmigrated. It was one of the best sniper rifles in the world. It had powerful lethality and could rival a martial grandmaster. After Fan Xian had this sniper rifle, no one dared to easily become his enemy.
Qing Yuannian opened the box and found a Barrett sniper rifle and letters for Wu Zhu and Fan Xian. The chest was divided into three layers. The first layer was the Barrett sniper rifle, which Ye Qingmei had left behind to deal with the Qing Emperor. The second layer was a letter to Wu Zhu. It expressed Ye Qingmei's longing for Wu Zhu and hoped that he would destroy the box after reading the letter to prevent it from falling into the wrong hands. The contents of the third level were not mentioned.
After Qing Yuannian opened the box, he found a Barrett sniper rifle and two letters inside. The first level was the Barrett sniper rifle, which Ye Qingmei had left behind to deal with the Qing Emperor. The second layer was a letter to Wu Zhu. It expressed Ye Qingmei's longing for Wu Zhu and hoped that he would destroy the box after reading the letter to prevent it from falling into the wrong hands.
Qing Yunian's box contained a Barrett sniper rifle and two letters. The first level was the Barrett sniper rifle, which Ye Qingmei had left behind to deal with the Qing Emperor. The second layer was a letter to Wu Zhu. It expressed Ye Qingmei's longing for Wu Zhu and hoped that he would destroy the box after reading the letter to prevent it from falling into the wrong hands. Therefore, when Qing Yuannian opened the box, he found that it contained the Barrett sniper rifle and two letters.
The box in the TV series "Celebrating Years" was opened in episode 28. Fan Xian successfully broke into the empress dowager's bedroom and stole the key. He inserted the key and entered the password to open the box with three layers of contents. The box contained a Barrett sniper rifle and two letters Ye Qingmei had left for Wu Zhu and Fan Xian. The first level was the Barrett sniper rifle, which Ye Qingmei had left behind to deal with the Qing Emperor. The second layer was a letter to Wu Zhu. It expressed Ye Qingmei's longing for Wu Zhu and hoped that he would destroy the box after reading the letter to prevent it from falling into the wrong hands. Therefore, Qing Yunian's box contained a Barrett sniper rifle and two letters.
Well, it might contain something magical like a potion that grants wishes. Or maybe it holds old family heirlooms that carry sentimental value. It really depends on the author's imagination!
Ye Qingmei's box contained an M82A1 heavy sniper rifle.
Ye Qingmei's box contained a sniper rifle (Barrett M82A1). This was mentioned in both the original novel and the TV series. Other than the sniper rifle, there were letters for Fan Xian and Wu Zhu in the box. They described Ye Qingmei's experiences and how she missed her. After Fan Xian opened the box, he found the sniper rifle and the letter Ye Qingmei had left for him.
Ye Qingmei's chest contained an M82A1 heavy sniper rifle, letters for Fan Xian and Wu Zhu, and abortion medicine for Fan Xian.
No one really knows for sure. It's one of the mysteries of the movie that's left to your imagination.