Abstract: Optimizing the working performance of diesel engine and improving the rationality of power supply through PID controller is the key research direction of diesel engine electronic control technology optimization.Especially for tractors, their application forms in agricultural production are diversified, and supporting different kinds of agricultural machines and tools will produce different operating load and load change characteristics, as the types and functions of tractor supporting machines and tools are constantly enriched, the control accuracy of tractor field operation is significantly improved to ensure good adaptability to different working conditions and different load conditions.Based on this, starting from the load influencing factors of tractor diesel engine, this paper analyzes the main force relationship affecting diesel engine load during tractor operation, analyzes the differences between constant speed and growth conditions, determines the primary and secondary relationship of diesel engine load influencing factors, and designs the parameters and model for the PID control of diesel engine in combination with the operating characteristics of tractor, the rationality of PID control is simulated, and the later development direction of PID control under two-dimensional fuzzy control is explained.