The invention discloses a water lubricated bearing and transmission system comprehensive performance testing platform, which comprises a water lubricated bearing, a dynamic seal device, an elastic coupling, a gearbox, a water circulating system, a driving motor, an intermediate bearing, a bearing block, a loading and testing device and other parts. The loading device loads a test shaft in the circumferential direction, axial direction and radial direction so as to simulate complicated working conditions of the water lubricated bearing and the transmission system thereof; the testing system can detect various parameters of the water lubricated bearing, such as working speed, torque, temperature, frictional characteristics, water film pressure distribution, interface deformation distribution, shaft centerline orbit, noise and dynamic characteristics, and comprehensive performance of the dynamic seal, the elastic coupling and the transmission system on line; and the testing platform can be applied to research of scientific problems such as the loading bearing of a water lubricated friction pair, failure mechanism and evolution law, tribological performance and dynamic service behaviors, and provides a key scientific and technological basis for developing a pollution-free, low-noise, high-reliability, long-life, high-efficiency and energy-saving water lubricated bearing and a transmission system thereof.