Aimed at the problems that the ballistic missile is quick in speed, the RCS of radar is small and it is very difficult for the early-warning radar to track the whole early-warning course, the improved GM (1, 1) model is advanced to predict the position information of the ballistic missile. The smooth degree of original date sequence, the conformation method of background value and the beginning condition are improved in the new model, at the same time, an improved new model is built and the modeling steps are put forward. The simulation result shows that compared with the traditional GM (1,1) model, the prediction precision of the improved model is greatly improved and the application area is extended, so it can be used to predict the position information of the ballistic missile.