Abstract: The design principles for T3 test valve timing was presented in the thesis. Combined with the new CPR1000 project DCS platform, the research of T3 test valve stroke time measurement design to meet the design demand was focused on. And the compliance with design principle, the time measurement signal path, and the time measurement accuracy of hard wiring and network were analyzed. Finally, according to the DCS structure and equipment characteristic analysis, a method of time measurement by ESF (engineered safety features) AT (automatic tester) was provided, which is a method of some potential for the follow-up CPR1000 project.