Horizontal test method for revolve-body polar moment of inertia

The invention relates to a horizontal test method for revolve-body polar moment of inertia. During horizontal test of polar moment of inertia, a revolve body is tightly held through a steel ring; in a state of equilibrium, a product torsionally vibrates freely along the rotary axis direction of the product when an instantaneous driving moment is exerted to the steel ring. The moment of inertia, namely the size of the polar moment of inertia of the product along a rotary axis can be calculated out by measuring the torsional vibration cycle of the product. With the method, the revolve-body polar moment of inertia can be effectively tested, convenience in test is achieved, and the method is small in test error and high in precision.