The invention provides a virtual test method for a rail wagon body fatigue test. The method comprises the steps that 1, a rail wagon body model is built; 2, a connecting structure model is built; 3, a test bed model is built; 4, a drive signal of the test bed in actual running is obtained, and the drive signal is loaded in the test bed model. According to the technical scheme, the problem that in the prior art, the gap of the rail wagon body virtual fatigue test result and the rail wagon body actual fatigue test result is large is solved.