Li Delun was born in Beijing in 1917 and began learning piano and violin in his early youth. In 1940, he was admitted to the Shanghai National Conservatory of Music, where together with fellow students he organized the "China Youth Symphony Orchestra." After graduating in 1946, he went to Yan'an where he served as teacher and conductor of the Central Orchestra of China.
After the founding of the People's Republic of China, he became a conductor at the China National Opera House. From 1953 to 1957, he studied under Nikolai Anosov at the Moscow Conservatory and returned to the Central Orchestra of China after graduation. He conducted orchestras in the Soviet Union, Finland, the Czech Republic, Cuba and other countries and performed with many famous musicians including David Oistrakh, Yehudi Menuhin, Isaac Stern, Yo-yo Ma, Fu Ts'ong, Liu Shih-kun, and Lu Siqing, etc.