Automatic mechanical transmissions (AMT) are suitable for use in heavy duty vehicles. Bench testing is an important task of the research and development. Many objectives, such as AMT performance testing, matching AMTs with engines, and optimizing control rules, can be achieved through bench testing, thereby laying a foundation for AMT application. An AMT testing bench is built up based on a developed AMT. By analyzing the performance requirements of AMT bench testing for heavy duty vehicles, a testingcontrolling system scheme is proposed and methods of data acquisition and communication are analyzed. Control methods for actuators are proposed based on analyzing the characteristics of AMT actuators. A testingcontrol program for AMT bench testing is developed based on the Delphi platform. The entire bench testing system possesses advances test functions.