The invention discloses a low-temperature low-pressure adsorption performance testing device and a testing method thereof. The device comprises a vacuum container, a low-
temperature unit, an adsorption unit, a gas distribution unit, a vacuum unit, a buffer unit and a
data acquisition unit, the gas distribution unit independently provides working medium gas and test gas for the low-
temperature unit and the adsorption unit; the low-
temperature unit performs gradient pre-cooling on the working medium gas and the test gas; the adsorption unit is in heat-conducting connection with the low-temperature unit; the buffer unit is used for performing multi-stage
pressure stabilization and flow control on the test gas; the vacuum unit is used for independently vacuumizing each unit; the
data acquisition unit monitors pressure parameters. The test method comprises the following steps: vacuumizing to an initial high
vacuum state, introducing working medium gas for
refrigeration and temperature stabilization, carrying out gradient pre-cooling on test gas, carrying out multi-stage
pressure stabilization, introducing the test gas into the adsorption unit, recording balance
pressure data, and calculating the adsorption quantity. According to the invention, a stable low-temperature environment can be provided for adsorption performance testing,
refrigeration vibration interference is isolated, and the stability of adsorption testing is improved.