Abstract: In order to research the influence of long cable on performance of frequency-conversion and speed-regulation of shearer, loading tests of traction cables with different lengths were done. The theoretical analysis and experimental results show that the effects to frequency converter and motor caused by output cable have close relationship with the length of the cable. As cable length increases, the bad effects become more serious. The negative effects caused by long cable on performance of frequency-conversion speed-regulation system of shearer can be reduced by optimizing frequency converter parameters to improve load capacity of the motor, and using filter to restrain output harmonic of frequency converter.