The invention relates to a temperature control and pressure control liquid storing tank device. The temperature control and pressure control liquid storing tank device is characterized by comprising a tank body (1), a liquid outlet pipe opening (11), a liquid supplementing pipe opening (12), an air intake/exhaust pipe opening (13) and a liquid inlet pipe opening (14). An electric heater (2) is arranged on the outer side face of the middle lower portion in the tank body (1). The liquid outlet pipe opening (11) is connected with a circulation pump (7). The outlet end of the circulation pump (7) is connected with a circulation pipeline (74), a heat exchange pipeline (75) and an output pipeline (71). The circulation pipeline (74) is connected with the heat exchange pipeline (75) in parallel. A cooling heat exchanger (6) is connected to the heat exchange pipeline (75) in series. A circulation circuit (3) is connected between the circulation pipeline (74) and the bottom of the tank. A pressure transmitter (8) and a temperature transmitter (9) are arranged on the top of the tank body (1). The temperature control and pressure control liquid storing tank device is reasonable in structure, capable of outputting liquid of which the output temperature and the pressure can be controlled, especially applicable to a detection system of a mechanical sealing device and capable of providing working conditions of a simulated fluid and improving the detection precision of the mechanical sealing device.