Li Mubai (1913-1991) was born in Haining, Zhejiang Province. In 1928, he settled in Shanghai and joined the Zhiying Studio, where his cooperation with Jin Xuechen started. The two soon became partners, a partnership that lasted for several years. The two created many commercial calendar posters together, although they would sign separately: Li would sketch the human figures, while Jin would paint the clothes and accompanying scenery. Together with Jin Meisheng, they were known as the "Three Pillars of Calendar Posters". Li's specialty was watercolors, but he was also skilled in oils. He was especially good at depicting the youthful skin of young women and children.

After 1949, Li became council member of both the Chinese Artists Association and its Shanghai Branch. In 1954, he was employed on a special basis by the Shanghai Poster Publishing House, which later merged with the Shanghai People's Fine Arts Publishing House (上海人民美术出版社, Shanghai renmin meishu chubanshe), one of the main producers of propaganda posters. From 1956, Li headed the Mubai Painting Studio to train young painters.