Abstract: Disclosed are a heavy oil activator, a preparation method and use thereof. The heavy oil activator has a structural formula shown in Formula (1). In Formula (1), x, y, z, m, and n are respectively mass fractions of corresponding chain segments in the polymer, m being 0.75-0.85, y being 0.20-0.24, and x, z, and n all being 0.001-0.01; and p is a natural number between 2 and 9. The activating polymer provided has the effects of increasing viscosity of an aqueous phase while reducing viscosity of crude oil, and can serve both as a displacing agent and a viscosity reducer to realize integration of the two agents.