Air-drop excitation inrush suppression method for a Yyn0 type three-phase group-type transformer The method includes the steps of a protective device sampling and recording voltage and current of mutual inductor during a switching on process of transformers, determining the current blow-out sequence and voltage blow-out phase angle according to the sampled three-phase voltage current waveforms, and finally determining the switching-on sequence and switching-on phase angle of the transformers according to the information. Only three-phase voltage current waveforms during operation of the Yyn0 type three-phase group-type transformers are sampled to obtain the three-phase current blow-out sequence and voltage blow-out phase angle information, so as to determine the switching-on sequence and switching-on phase angle. In this way, the zero load switching-on excitation inrush can be suppressed. Related parameters can be easily obtained, and the method can be conveniently applied in actual engineering.