Aiming at the control strategy of digital switching power supply,a BP neural network PID control system with improved conjugate gradient algorithm is proposed.Takin g BUCK converter as the research object,on the basis of BP neural network,the regulat ion time and recovery speed of the control system are optimized by improving conjugate gradient algori thm and combined with PID algorithm,in order to achieve the optimization of the control performa nce and output performance of the digital switching power supply system.At the same time,base d on the MATLAB platform to complete the system modeling,The BP neural network PID control syst em and the BP neural network PID control system with improved conjugate gradient algorithm wer e simulated by MATLAB software.The results show that the adjustment time of the improved contr ol system is 0.03s higher,the overshoot is 10% lower,The rise time is 0.015s lower than bef ore improvement, and the recovery time is 0.03s shorter than that before the improvement.It is v erified theoretically that the BP neural network PID control system with improved conjugate gradient a lgorithm has shorter response time,lower overshot and stronger anti-interference ability th an BP neural network control system.