The invention relates to an electric energy monitoring method, an electric energy monitoring device, electric energy monitoring equipment and an electric energy monitoring system. The method comprisesthe following steps of obtaining sampling information of a power supply power source output by a mutual inductor; determining the practical variable ratio parameter of the power supply power source according to the sampling information; judging whether the practical variable ratio parameter is consistent with the theoretical variable ratio parameter of the power supply power source or not, wherein the theoretical variable ratio parameter of the power supply power source is obtained from a prestored precision variable parameter model of the mutual inductor; if the practical variable ratio parameter is not consistent with the theoretical variable ratio parameter, calibrating the practical variable ratio parameter into the theoretical variable ratio parameter; and determining the power supply information of the power supply power source according to the theoretical variable ratio parameter. By adopting the technical scheme, under the condition of error existence in the sampling information of the power supply power source output by the mutual inductor, the precise power supply information of the power supply power source can be obtained; and the electric energy monitoring precision is improved.