Because of insufficient sensitivity of the transformer differential protection in protecting the single-phase ground fault, the necessity of the zero-sequence differential protection of the transformer is discussed. However, due to human factors, such as zero-sequence current transformer wiring error, protection setting error, zero-sequence current transformer selecting error, and so on, zero-sequence differential protection incorrect action accidents often occur. These errors of zero-sequence differential protection cannot be verified by the normal load current, which limit the application of zero-sequence differential protection. In this paper, the zero-sequence differential protection is configured with self-checking function, which uses the magnetizing inrush current to verify the correctness of zero-sequence protection circuit, and is proved to be correct by dynamic simulation and experiment test. The self-checking function does not require manual participation, is reliable and practical, and can effectively prevent incorrect action of zero sequence protection caused by human error.