The invention discloses a failure testing method of a coupling device. The method comprises the steps that rotation rate data of an output end of the coupling device and rotation rate data of an inputend of the coupling device are obtained in real time in the testing process; a relative torsional angle of the coupling device is calculated according to the rotation rate data of the output end of the coupling device and the rotation rate data of the input end of the coupling device; resonance frequency range of shock-absorbing rubber of the coupling device is calculated according to the relative torsional angle; the rotation rate of an engine in the testing process is obtained in real time, and the firing frequency range of the engine is calculated according to the rotation rate and the cylinder number of the engine; whether or not there exists an overlapping region between the resonance frequency range and the firing frequency range, if yes, the failing risk of the coupling device exists, and if not, the failing risk of the coupling device does not exit. The method has the advantage that the failing risk of the coupling device can be conveniently and accurately detected.