Abstract: A method to reform the traditional Engine Test-bed system is introduced. The reformed test system can not only largely improve testing precision and reliability, but also accomplish experiments under variable running parameter. Because of it's economization this Engine Test-bed system is of great value to many engine producers and researchers. We developed the whole software system by VC++ under Windows operating system. Its graphical user interface and powerful data processing function prove that the reformed system has much better performance than the old engine-bed test system.