Abstract: A new method of susceptibility test in reverberation chamber based on statistics theory is proposed in this paper.With the purpose of getting the testing method,the statistical mean time which can solve the problem of unsteadiness field is defined.And the results from this method are validated by a large number of susceptibility experiments in the lab.When RC in stirred mode,the susceptibility threshold should be the statistical mean field strength of the location where the antenna is.While in tuned mode,the threshold should be the mean field strength of all the independent positions.The experiments show that this method is simple and can obtain the susceptibility threshold at any frequency with well repeatability.The comparison between first and second edition of IEC61000-4-21 is presented in this paper and the results are also validated.