Sun Daolin (1921-) made his debut on the screen in 1948 and has played the leading role in nearly 20 films. He played Company Commander Li in the feature film Scouting across the River, and impressed audiences for the first time in his career. Later, he appeared as Juexin in Family and his exquisite performance depicted in detail the inward contradictions and depressions of a petty intellectual.  

In 1958, he played Li Xia, an underground worker of the Chinese Communist Party, in The Electric Wave Never Dies, marking a big leap forward in his performing art. Li Xia appeared in different capacities in the film. Sometimes he is a boss, and sometimes he is a factory worker. Sun Daolin concentrated on the changes in the role. The makeup, clothes, and tone in Li Xia's speech change, but his true nature as the Party's underground worker remains unchanged. The righteousness in Sun's furrowed brows, which reveals the quality of an army man, is ideal for the portrayal of Li Xia's heroism. Sun's performance was praised by people in the cinema circles.

On the Threshold of Spring is Sun Daolin's most representative film. He fully brought to light Xiao Jianqiu's gentleness in appearance and profoundness at heart as well as his complicated and contradictory feelings. The portrayal of Xiao Jianqiu by Sun Daolin became a unique image with lasting vitality on China's cinema screens.

After the Cultural Revolution, Sun joined hands with Rentaro Mikuni, a well-known Japanese cinema actor, in An Unfinished Game of Go, a film jointly produced by Chinese and Japanese companies. He played Kuang Zhongshan, a Chinese go player, and his simple, natural, deep and true-to-life performance was highly spoken of.