Abstract: Based on pole assignment, a simple self-tuning control algorithm with PID structure is proposed. This algoritim is simple in structure, easy realized, robust and also applicable to non-minimum phase system. Moreover, this algorithm has found application in controlling a group of cover annealing furnaces with microcomputer in an iron and steel company. Real-time control result shows that the proposed algorithm has good steady-state regulating and tracking properties, and control performance is much better than that of the traditional instrumental PID regulator. It is also applicable to other slowly varing systems.