In " Autumn Thoughts on the Clear Sky Sand," the sentence that pointed out the main theme and expressed the sorrow of a wanderer at the end of the world was " The setting sun is setting in the west, and the heartbroken person is at the end of the world." Through the description of the setting sun, this sentence expressed the homesickness of the wanderer and highlighted his lonely, helpless and lamenting fate. This sentence was quoted many times by the author Ma Zhiyuan as the representative famous sentence of " Tianjing Sands." It was also one of the common expressions of the pain of separation in Chinese literature.