This article describes the Parabolic trough solar collector design of single-axis tracking system based on PLC, Siemens S7-300 as a controller, using a complex mathematical model, based on the special climate of Western Region, select the single-axis design process, greatly reduced cost, collectors need only be completed that automatically tracks the sun azimuth. Feedback device selection angle sensor, light intensity sensor and sun sensor, strain two conditions that cloudy and sunny, which greatly improves the efficiency of the collector, the better to achieve real-time tracking grasp the situation.