Belousov, a Muscovite by birth, became head of the department of geodynamics at the Soviet Academy of Sciences, Moscow, in 1942 and was later (1953) made professor of geophysics at Moscow University. His main work concentrated on the structure and development of the Earth's crust. In 1942 he put forward his theory on Earth movements, in which he proposed that the Earth's material has gradually separated according to its density and this is responsible for movements in the crust. He at first rejected theories on continental drift.

Belousov became chairman of the Soviet Joint Geophysical Committee in 1961. His works include Principles of Geotectonics (1975).