Fang Junbi was born in Fuzhou in 1898 to a wealthy and progressive family of merchants. Her brother Shengdong was one of the martyr heroes of the Guangzhou uprising of 1911. After the 1911 revolution, her sister Junying, who was close to anti-imperial groups, travelled to France to study, in 1912. Fang Junbi, then 14 years old, accompanied her. There, she became associated with members of liberal circles who had adopted Western culture, and studied under the reformist scholar Cai Yuanpei and the revolutionary Wang Jingwei. She felt drawn to art and began studying Western techniques at the Académie Julian in Paris in 1917, before the bombardment of the First World War forced her to pursue her training at the École des beaux-arts in Bordeaux. Upon returning to the French capital in 1920, she became the first Chinese female student to enter the École des beaux-arts in Paris, where she met the painter Xu Beihong. Two years later, she married the poet and politician Zeng Zhongming.
In 1924, she was the first Chinese female artist to have her work shown at the Salon Annuel des Artistes Français, where she made a positive first impression with her Flute Player (1924). The oil painting, which was reproduced on the cover of the review Annales politiques et littéraires, combined European technique and Chinese iconography. The following year, she returned to China, where she taught Western painting at the Zhixin College and where her work garnered some attention. She made several trips to France between 1926 and 1930 and became a member of the Salon des Tuileries in 1928. She returned to her country in 1930, and by 1932 she had begun using Chinese pictorial techniques under the tutelage of masters of the Lingnan School, Gao Jianfu and Gao Qifeng, whose approach, reconciling the aesthetics of both continents, was in accordance with her own explorations. However, rather than copy the ancient masters, she innovated and employed traditional Chinese methods to paint from life while also making use of her knowledge in the Western science of form. This effort to synthesise both approaches was pointed out by Cai Yuanpei in 1938.

The following year, she was the target of an attack in Hanoi, as was her husband, who died from his injuries. Painting helped her get through the ordeal. She was forced to leave the country in 1949 after the establishment of the People’s Republic of China, settling first with her three sons in Paris, where her work was regularly featured at the Salon de la Société nationale des beaux-arts from 1950 to 1954. Her paintings caught the eye of the director of the Musée Cernuschi René Grousset, who praised her work in a text from 1951. In 1957, she decided to relocate with her family to Boston. From the 1950s to the 70s, she showed her works in Tokyo, Kyoto, Taipei, Hong Kong, as well as in the United States, Argentina, Brazil, and Lebanon. She only returned to visit China in 1972 and would subsequently make several trips there subsequently. In 1978, on the occasion of her 80^th birthday, a retrospective was organized at the Hong Kong Arts Centre. Her artistic contribution was celebrated in 1984 with a major exhibition of her works at the Musée Cernuschi. She died in Geneva in 1986. Her strong attachment to her native country led her to donate forty of her paintings to the Chinese state in 1978.