Abstract: In view of problems of low developing efficiency and reliability due to manual programming in traditional developing procedure of control system, the paper proposed a design method of real-time control system of DC motor based on xPC Target. The method employs code automatic generation technology and xPC real-time kernel of Matlab, builds control loop by using industrial control computer as controller and DC motor as controlled object, combines controller application program by using Simulink modular, realizes code generation, compiling and downloading of application program in target-host mode. The experiment result shows that code generation of the control system is fast and reliable, and the control system is more effective and stable by use of the method.