The invention discloses a device and a method for testing the performance of a mobile communication network. The method comprises the following steps of: generating a switching instruction according to a preset test strategy; switching an outdoor donor antenna and an indoor retransmission antenna to form a test path in accordance with the switching instruction; coupling a signal transmitted by the test path, executing a corresponding test in the performance of the mobile communication network according to the switching instruction, and acquiring test information; and packaging the test information, and coupling the test information to the outdoor donor antenna for transmission. By the device and the method, the utilization rate of equipment can be increased, test functions can be expanded, and test cost can be decreased.