The invention relates to a method for detecting a switchgear defect based on transient ground voltage and ultrahigh frequency. The method comprises the steps of detecting a switchgear by means of a transient ground voltage detecting method and an ultrahigh frequency detecting method respectively, thereby respectively obtaining a corresponding phase-amplitude graph and a pulse current oscillogram;obtaining the characteristic parameter of the phase-amplitude graph; identifying the characteristic parameter of the amplitude-phase point graph of a partial discharge signal by means of an artificialneural network; matching the characteristic graph of the discharge pulse waveform by means of a sift characteristic algorithm; and respectively generating the amplitude-phase point graphs of the partial discharge signal, the result of the partial discharge pulse waveform, a suggested result and reliability thereof according to the two methods according to the weights of the two methods. Accordingto the method of the invention, the transient ground voltage detecting method and the ultrahigh frequency detecting method are combined; through performing determination according to the amplitude-phase point graph and the partial discharge pulse waveform of the partial discharge signal, an artificial error caused by individual differences can be effectively reduced, and identification accuracy is improved.