The invention discloses a moving die test method by use of a restraint subsynchronous resonance (SSR) device, which comprises the following steps of: starting a frequency converter, generating a signal with the preset frequency by a signal generator, and adding the signal into a control device of the restraint SSR device so as to activate a generator to generate torsional vibration; measuring thephase difference between the signal generated by the signal generator and a feedback signal of a unit rotation speed so as to determine a correction parameter for phase correction; generating a subsynchronous signal by the frequency converter, and switching the restraint SSR device to a restraint state; superimposing a subsynchronous torque with the preset frequency in the output torque of the frequency converter, switching the restraint SSR device to a closed-loop restraint state, and monitoring the subsynchronous rotation speed signal with the preset frequency of the generator; if the subsynchronous rotation speed signal with the preset frequency of the generator is monitored and attenuates to the preset amplitude, finishing the step; and if the subsynchronous rotation speed signal doesnot attenuate to the preset amplitude, returning to the step d to adjust the correction parameter so that the subsynchronous rotation speed signal attenuates.