The development of real time hardware systems tends to be module-based as the systems become more and more complicated. Two methods of modules controlling and features are studied. Based on the research of general methods for modules controlling and the analysis of module functions of MPEG-2 encoder, a suitable method of controlling the modules of the encoder is presented and the hardware and software implementations of its controlling module are analyzed in detail. This controlling method is proved to be capable of guaranteeing the reliability of the real time system.