The invention discloses a water bath testing device with temperature difference alternating. The water bath testing device comprises a main control system (1); the main control system (1) is located at the center of a ring testing base structure (6); the ring testing base structure (6) is provided with a plurality of water bath heating devices (4); the water bath heating devices (4) are internallyprovided with temperature detecting and controlling elements (5) used for controlling the temperature; the water bath heating devices (4) are arranged circumferentially with the main control system (1) as the center; the main control system (1) is provided with a rotating device; the rotating device drives one end of a component clamping device (2) to rotate with the main control system (1) as the center; and the other end of the component clamping device (2) is connected with an electric push rod (8) driving a sample to move up and down. According to the water bath testing device with alternating temperature difference, simulation of temperature change in area with large temperature difference in actual environment is achieved, and alternating between the temperature difference and temperature amplitude is achieved automatically.