The invention provides a reliability test loading device for a rolling linear guide rail and ball screw system and a using method thereof. The reliability test loading device for the rolling linear guide rail and ball screw system comprises an X-direction load loading assembly, a Y-direction load loading assembly and a Z-direction load loading assembly, and realizes a mode of uniform stress in theY-direction and the Z-direction and sliding loading. A novel machine tool performance test method is provided. After the test loading device is assembled and used with a machine tool to be tested, the load application on a linear guide rail and a ball screw pair in the linear feeding movement of the machine tool can be truly simulated without consuming material objects and machining tools, the machine tool performance test cost is effectively reduced, and the machine tool manufacturing cost is effectively reduced while the excellent performance of the machine tool is ensured.