Abstract: To study the waterproof capability of water rotary joint with mechanical seal under running-with-load condition and guide its research and development, this article develops the comprehensive test equipment for water rotary joint based on previous equipment. The principle, overall structure and performance of the test equipment are introduced. The test equipment is composed of temperature control system, pressure and flux adjusting system, servo-driving system, data acquisition and processing system. In this equipment, temperature is controllable and rotation speed is adjustable. It has friendly operating interface, provides readable test data, and can perform running test under different pressure and flux. The comprehensive test equipment provides an effective means for the research and development and the performance evaluation of the products of water rotary joint.