±800 kV UHVDC system plays an important role in resource allocation. The characteristics and configuration of UHVDC protection are introduced, and on the basis of contrast analysis in DC protection configuration and function logic of Yun-Guang project and Nuozhadu project, the optimization of UHVDC protection is researched. It emphatically introduces the configuration principle, logic, and optimization of converter DC differential protection (87DCM), metallic return line longitudinal differential protection (87MLL), DC filter C1 capacitor unbalance protection (60/61DF) in Nuozhadu project. The optimized configuration and logic of the DC protection can improve its speed and reliability, enhance the UHVDC system stability, also have certain reference value on the operation and maintenance in the other HVDC system and the design of the subsequent project.