UHVDC multi-terminal hybrid transmission system adopts a double valve group series connection，and the failure of a valve group will have a great impact on the system. After a single valve group fails，we hope to minimize the impact of the failure，ensure the sustainable operation of the system，and improve the overall operating time. The control system must react quickly to remove the failed valve group to avoid affecting the normal operating valve group. The valve group failure exit control strategy in converter high-voltage DC （LCC-HVDC） projects has been widely used in various projects，but voltage source converter ultra-high-voltage DC（VSC-UHVDC） systems and UHVDC multi-terminal hybrid systems have no previous engineering application in the industry. Therefore，it is necessary to research valve group failure exit control method for UHVDC multi-terminal hybrid system. This paper proposes a fault-valve group exit control method based on the hybrid bridge modular multilevel converter（MMC） valve，a hardware closed-loop test is performed on the RTDS test platform. The RTDS test results prove that the control method proposed in this paper can quickly isolate the failure valve group and adjust the operating state of the system after the failure of a single valve group，without causing the entire system to be shut down.