By combining RTDS platform of HVDC primary system with actual control device of HVDC project, the simulation and verification platform of HVDC project is built, which has the problems of large area and complex wiring. A real-time simulation technology for HVDC transmission control and protection system is proposed. And the HVDC control and protection program is built one by one by using the graphical method of Matlab/Simulink. Then the graphical program is transformed into a CBuilder code file through code conversion and multi-threaded optimal scheduling scheme, and a highly integrated RTDS custom component is constructed. Only one single RTDS computing unit is used to realize the calculation of control and insurance program of the whole HVDC project converter station. The proposed technology is validated on RTDS simulation platform, and the experimental results show that the technology is effective and feasible. The simulation technology makes the real-time simulation of AC/DC hybrid power grid more economical and efficient. This work is supported by National Key Research and Development Program of China (No. 2016YFB0900600).