In July of the first year of Qin Ershi (209 BC), after the uprising of Chen Sheng and Guangwu, Sean gathered people to respond. He soon belonged to Liu Bang, and later became an important counselor of Liu Bang. He assisted Liu Bang in formulating his operational strategy and put forward many important suggestions politically and tactically. These suggestions played an important role in Liu Bang's victory in the Chu-Han War and the establishment of the Western Han Dynasty. When Liu Bang entered Xianyang and saw the curtains, dogs and horses, treasures and women in Qin Gong, he wanted to stay in the palace. Sean said that he entered the State of Qin just to be happy, which was "helping others to abuse". Hearing the news, Liu Bang immediately returned to the army and won the support of Qin Min. After Xiang Yu entered the customs, the relationship between Liu and Xiang was tense and explosive. Sean persuaded Liu Bang to make peace at the Hongmen banquet, saved his strength, dredged Xiang Yu's uncle Xiang Bo, and let Liu Bang get away with it.

In the second year of the Han Dynasty (the first 205 years), Liu Bang was defeated in Pengcheng World War I. Sean suggested that Liu Bang strive for Ying Bu, Peng Yue and Han Xin to jointly resist Chu, which laid the foundation for the strategic encirclement of Xiang Yu in the future.

When Chu and Han were deadlocked in Xingyang, in order to get rid of the predicament, Liu Bang once wanted to adopt Li's suggestion and re-establish six countries to contain Xiang Yu. Sean tried to explain his shortcomings. Liu Bang's sudden change of heart had a great influence on the Chu-Han War and the subsequent situation. After Liu Bang became emperor, Sean was named Liu Hou. He persuaded Liu Bang to seal the feud of Yongji to appease the hero's dissatisfaction. He argued for the establishment of the capital in Guanzhong and the establishment of Prince Wei Liu. These suggestions are helpful to adjust the internal relations of the ruling class and stabilize the feudal ruling order.