A method for measuring heat dissipation of electromechanical device includes: S1. establishing a measuring apparatus; S2. measuring and obtaining data: a mass flow m corresponding to each cooling medium flowing through a housing, a temperature T1 of a liquid inlet, a temperature T2 of a liquid outlet, a temperature T3 of an air inlet, a temperature T4 of an air outlet, a temperature T5 of the inside wall of the housing, a temperature T6 of the outside wall of the housing, a total area A of the inside wall of the housing, and a wall thickness L of the housing are measured by the measuring elements; S3. calculating the heat dissipation. The heat dissipation of the electromechanical device under a working condition is measured so as to provide a reference for the heat dissipation design of electromechanical device.