In order to realize the efficiency management of the transformer neutral point earthing in substation, and the zero-sequence network stability, based on the research of the new generation protection and control technology of smart substation, one transformer neutral point earthing switch’s smart switching method which is realized based on substation protection technology is proposed. This method takes full advantage of the standard information exchange and sharing mechanism of the substation protection, the study of the smart switching principle and the specific implementation finally comes to the achievement of the earthing switch’s fast, reliable and automatic control. The analysis shows that this method can solve the problems of traditional ways, for one thing, the complex operation, the complicated construction and the security risks. In a word, this method can effectively realize the digitalization, automation and informatization of the neutral point of the transformer in the substation, which can improve the operation control of the power system availably.