Statistical Process Control (SPC) is an important tool for quality control in manufacturing process, which includes a series of activities such as process monitoring, process diagnosing and improving etc. In this paper the technique of statistical process control is used in the quality management of steel coil. Through a case the application of Per-defect Control Chat is introduced to prove the practicability of SPC method in the steel coil quality analysis and control. First the system samples the technological data, then uses the quantity to control chart. The system not only monitors the technological data but also calculates and analysis the process capability index, monitors the technological data. When the process get out of hand, by analyzing the reasons and taking timely corrective and preventive action, we can ensure process consistency and stability, improve the process yield.