The faults of wire feed system account for over 70% of the total faults of welding robot. It is the main cause of welding defects such as undercut,slag inclusion,partial welding,large granular spatter and burn through,which seriously restricts the production efficiency and cost of company. The fault locations of wire feed system are summarized as "4 sections and 1 wire",namely welding gun section,gun cable section,wire feeder section,external wire feed pipe section and welding wire section. By means of eliminating method,the fault of wire feed system is accurately located. Based on the wear condition of welding consumables,the aging condition of parts and the quality condition of accessories,the causes of wire feed system faults are analyzed step by step and the corresponding solutions are proposed,which provides useful reference for the high efficient application of welding robot.