This paper introduces the DPS-3000 platform which is first used in UHVDC power transmission project, analyzes the overall design scheme, measurement system design scheme, protection function configuration scheme and auxiliary function design scheme of the DC protection system based on this platform. This paper introduces the simulation test for secondary system which is in charge by manufacturer for the first time in China, analyzes the key technical problems found in the experiment and then proposes the solution strategy. The simulation tests for secondary system verify that DC protection system implementation scheme and its performance meet the design specification’s requirements, and lay down solid foundation for on-site commissioning and favoring putting into operation of the UHVDC power transmission project.