The problem of electromagnetic compatibility caused by supra-harmonics in the frequency range of 2 kHz~150 kHz in the power grid is becoming increasingly prominent, but the relevant IEC standards have not yet given the standard measurement method, which directly affects the technical supervision and management of related electromagnetic compatibility. By comparing and studying the differences and shortcomings of the standards IEC 61000-4-7 and IEC 61000-4-30 on the measurement methods of supra-harmonics, this paper puts forward the appropriate improvement measures. Then, the improved measurement method is adopted to simulate and analyze the typical signals, and we study the influence of the difference between different measurement methods from the perspectives of spectrum leakage, aggregate bandwidth, and amplitude modulation detection. Finally, the effect of each measurement method is comprehensively evaluated by the measured data, and the application suggestions are given, which can provide a reference for the unified measurement of supra-harmonics in the range of 2 kHz~150 kHz.