Aiming at the testing difficulties of valve control equipment due to its large quantity of interface in VSC-HVDC transmission project, this paper designs a physical dynamic simulation testing system to realize the full access test of VSC-HVDC valve control equipment with large-scale nodes. An interface expansion device is developed, which can realize the full access and full function test for valve control equipment with large-scale nodes through a small amount of physical sub-modules. The software and hardware design scheme of the interface expansion device are introduced in detail. Full access and full function tests are carried out on the valve control equipment developed by Xuji Group for Yu-E project, which verifies the correctness of the proposed physical dynamic simulation testing system.