In order to improve the performance of seeker scan loop, a modified single neuron PID controller was put forward based on the rule of Hebb. Firstly, a single neuron PID controller was designed to achieve online adjustment of PID parameters on the basis of conventional PID controller and neuron studying regulation with better performance. Secondly, with the square of error selected as the performance index, a single neuron PID control algorithm was developed by means of negative gradient algorithm which contains an inertia part. Simulation results show that the modified algorithm has the advantage of faster response over conventional single neuron PID controller as well as the merits of robustness and anti-disturbance.