The invention discloses a zero sequence overcurrent protection method, system and device and a computer readable storage medium. The method can obtain the linear relation between the zero-mode inrushcurrent waveform and the unsaturated core magnetic density and three-phase remanence magnetic density through a zero-mode inrush current analytic equation comprising the saturated mutual inductance ofa transformer, high-voltage side self-leakage resistance, low-voltage side self-leakage resistance, system zero sequence reactance, system voltage, system magnetic density, unsaturated core magneticdensity and remanence magnetic density; can determine the value of the unsaturated core magnetic density in each phase of the three phases through an unsaturated core magnetic density expression. Therefore, after the zero-mode inrush current parameter is substituted into the zero-mode inrush current analytic mode, the zero-mode inrush current waveform can be obtained, thereby achieving the mathematical analysis of the zero-mode inrush current waveform, achieving the analysis of the influence of transformer parameters of different structure types on the magnitude of the zero-mode inrush current. The method can reproduce the waveform when the zero-mode inrush current occurs, and can set the protection criterion of a zero sequence overcurrent protection device, and avoids misoperation of thezero sequence overcurrent protection device.