The invention discloses a low-temperature valve performance testing system based on computer data collection. It includes low temperature test tank, low temperature valve to be tested, flange end cover, mounting base, electromagnet, liquid level sensor, self-pressurized liquid nitrogen storage tank, mechanical pump, measuring cylinder method flow test system, flow meter, pressure sensor, pressure Signal processors, thermocouples, temperature signal processors, computer data acquisition systems, safety valves, vent valves, pressure reducing valves, helium cylinders, gas coils, etc. The invention realizes centralized storage, display and printing, etc., and also realizes automatic control of the self-pressurization system of the liquid nitrogen storage tank, and improves the work efficiency, timeliness, accuracy and safety of the test. The electromagnet can be fixed by electrification, which improves the flexibility and economy of the whole operation process.