The electromagnetic environment of the substation is more complex, secondary equipment may be affected by electromagnetic interference and other factors, which will produce false data and thus lead to protection misoperation. However, conventional methods of transformer inrush current identification do not take into account the influence of false data interference on protection. By analyzing the influence of false data on different methods, it can be concluded that existing methods may slow-operate even mal-operate. To solve this problem, a new magnetizing inrush identification method based on similarity identification is proposed. The magnetizing inrush current and fault current are identified by comparing the waveform similarity between the detected current and the sinusoidal signal. Simulation results show that this method can identify inrush current quickly and effectively, and it can not be affected by false data to a certain degree. This work is supported by National Natural Science Foundation of China (No. 51477090) and Science and Technology Project of China Southern Power Grid Company (No. GZHKJXM20160038).