Mining motor and frequency converter interference connected to power line as well as its features were analyzed. The impact and influence of high current on power line when started motor were explained through working principles of synchronous and asynchronous motor, meanwhile, reasons of inverte widely used in coal mine were discussed. Based on existing problems of harmonic generation in power electronic switches and other nonlinear devices, characteristics of equivalent impedance of frequency converter were discussed, and input harmonic analysis was made to multiple rectifying technology, which obtained influence of harmonic order under different conditions.