After Liu Bei took Yi Province, Sun Qian was promoted and held a rank equal to Jian Yong.

He was recommended by the famed scholar Zheng Xuan,[2] a fellow Beihai man, to serve under Liu Bei as an Assistant Officer (從事).

When Liu Bei succeeded Tao Qian as the Governor (牧) of Xu Province in 194, an act said to have further added to Zheng Xuan's considerable reputation.

[5] In 214, after Liu Bei had successfully seized control of Yi Province (covering present-day Sichuan and Chongqing) from its governor Liu Zhang and established his new base in Chengdu (Yi Province's capital), he promoted Sun Qian to General Who Upholds Loyalty (秉忠將軍).

Warns Liu Bei, as he prepares to fight the invading Yuan Shu, that a trusted man needs to be in charge of Xiapi but Liu Bei's choice of Zhang Fei would end poorly with Xu falling into the hands of Lü Bu.

Once Zhang Fei is calmed down, via the slaying of Cai Yang, Sun Qian goes with Guan Yu to Runan to see Liu Bei then Sun Qian goes north to see Liu Bei who had gone to talk to Yuan Shao.

Is met by strong objections by Cai Mao who is wary of Liu Bei's track record with other lords and that inviting Liu Bei would invite an attack from Cao Cao so suggests executing Sun Qian as a signal.

Zhang Fei is sent to investigate news of Pang Tong getting drunk as head of Leiyang, Liu Bei also sends Sun Qian to act as a cooler head, Sun Qian persuading Zhang Fei to look deeper into the matter rather than just dismissing Pang Tong.

Zhang Fei is won over when Pang Tong sorts out a hundred days of neglected work by mid-day and thanks Sun Qian for preventing a loss of such a talent.