Yang was admitted to a girl's school at the West Hill Spa on the outskirts of Beijing when she was 13. A marked decline in her family's fortunes forced her to quit school and go to work to earn her own living. She was a primary school teacher in Dingxian, Hebei Province, and a private tutor in Beijing before she went to work in a bookstore. She began writing in 1934, publishing her essay "A Sketch of the Inhabitants in the Hilly Areas of Rehe Province" that same year. When the War of Resistance against Japan began in 1937, she went to the Shanxi-Chahar-Hebei Border Region, where she became director of the Women's Association for National Salvation in Anguo County as well as director of the Information Bureau of the Women's Association for National Salvation in central Hebei areas. In 1942, she became an editor with Dawn Light Daily, and later worked for Shanxi-Chahar-Hebei Daily and People's Daily, sometimes taking charge of these papers' supplements. Her novel, Life on the Reedy Lake (1949), is a realistic record of the Resistance War. After the founding of the People's Republic of China in 1949, Yang worked with the information department of the Women's Federation of Beijing. She was transferred in 1952 to the scenario board of the Central Film Administrative Bureau, once more taking up editing as her major pursuit.
Her novel The Song of Youth published in 1958 created a furor among readers throughout China and eventually became a best seller. Written in a free and lucid style, this work vividly depicts the strenuous life and unremitting struggle of the patriotic students led by the Communist Party of China during the momentous period from the September 18th Incident in 1931 to the December 9th Movement in 1935. In 1985, her second novel, The Best Song in Her Prime, tells of a girl student who, having suffered from mental agonies at university, throws herself into the war against Japan and the Liberation War.
Yang died on December 11, 1995 in Beijing.
Yang Mo's main works include The Song of Youth (1958), "Tenant" (1963), "My Physician" (1964), "The Red Morningstar Lily" (1964), and The Best Song in Her Prime (1986).