Because of systemic error in measurement and trajectory track, precision of trajectory parameter is not high and it results in false alarms in the traditional systems. The intelligent decision-making system of rocket safe controlling is built by using object-oriented method. First, the authors analyze and design rocket safety controlling architecture. Then, we study about knowledge expressing and knowledge database by object-oriented technique for the rocket safety controlling. At last, inference procession of the system is discussed. Intelligent decision-making system of rocket safety controlling is accurate, extensible and flexible.