Abstract: The linearing and decoupling mathematics model of cement raw material process is describedin this paper,and then the new self-tuning control stratigy is presented.The least square estimationmethodis impoved and a good composition estimation of raw material is obtained to solve the problem,i.e.the input signals of system are not persistently exciting.Either simulation experiments or practical operation shows that the new control strategy and improved estimation method is successful.Using PMC-88 industrial con-trol computer,this control strategy has been implemented and used for real-time operation in the cement plant.