Motor is the key part of the air conditioner compressor. And the production process of the motor will often encounter some quality defects. One of the most common defects is machine winding paint film injury. In the past, salt pinhole test and brush test are common means for product quality control in many companies. Although in such trials, some quality problem can be found, it is a single method for site quality management and is a kind of method of remedying afterwards. It often cannot find or visualized find by chart the bad trend timely. Statistical process control (SPC) is a different method, which can implement real-time monitoring and evaluation in each stage of the production process. It is a kind of preventive method. It can carry out the paint damage monitoring and evaluation in the motor manufacturing process very well, using SPC control diagram method.