In view of problem that current control method of speed-regulation system of DC motor has poor control effect caused by fixed parameters of PID controller, the paper put forward an adaptive PID control algorithm with quadratic single neuron, namely quadratic performance indexes was introduced in adjustment of weighting coefficients, and expecting optimization effect was gotten by calculating control law. The Matlab simulation result showed that the method can improve dynamic process performance of control system, reduce overshoot, shorten settling time and has some certain anti-interference ability.