The harmonic current emission limits index distribution for distorting loads is very important for both power supply department and consumer. In this paper, the consumer’s harmonic limit determination methods proposed by GB/T 14549-1993 and IEC 61000-3-6 are introduced, and their major differences are detailed as well. The paper suggests the national harmonics standard to apply coincidence factor in consumer’s harmonic limit calculation and mainly describes a method of determining the coincidence factor, particularly for the minimal coincidence factor of high-voltage distorting loads. With the results of theoretical analysis and statistic based on harmonic measurement data of electric railway, the necessity and reasonableness of this method is further confirmed.