The invention relates to a device and a method for testing the thermal insulation performance of a vacuum thermal insulation sleeve in a simulated frozen soil environment. The technical scheme is as follows: refrigeration equipment and frozen soil are installed in a sealed device, the upper end of a vacuum thermal insulation sleeve to be tested is sealed by a front sealing end and is connected with a drilling fluid circulation device at the outside the sealed device through a drilling fluid input pipeline, and the lower end of the vacuum thermal insulation sleeve to be tested is sealed by a rear sealing end and is connected with a flow meter at the outside of the sealed device through a drilling fluid output pipeline; and an external temperature sensor is installed between a cement sheathand the frozen soil, an internal temperature sensor is installed on an inner wall of the vacuum thermal insulation sleeve to be tested, and the data of the three components are respectively connectedto a data collection system. The device and the method have the beneficial effects that the device and the method can be used for evaluating the thermal insulation performance of the sleeve during thecirculation of drilling fluid with different temperatures, and can also be used for evaluating the thermal insulation performance when the sleeve is under different temperature formation conditions,the thermal insulation performance evaluation method of the sleeve is not limited by the size of the sleeve, the type of the sleeve, the temperature of the drilling fluid and the environment temperature, so that the application range is relatively wide.