From the perspective of space reliability requirements of spacecraft，a method for evaluating the material properties of low-temperature co-fired ceramic （LTCC） materials in a simulated space service environment was proposed in this paper， mainly including the conditions of large-temperature domain， temperature cycling，irradiation and the methods for evaluating the force/thermal and electrical properties after the tests.This method was carried out on a domestic LTCC material. The results show that the thermal conductivity decreases from 4.77 W/（m·K） at -65℃ to 2.89 W/（m·K） at 175 ℃，while the flexural strength decreases from 445 MPa at -65 ℃ to 310 MPa at 0℃ and stabilizes at about 310 MPa under the large-temperature test conditions.Although the coefficient of thermal expansion increases with the increase of temperature， the trend of change in temperature is basically consistent with similar imported materials.All the assessment items do not change significantly under the temperature cycling and simulated space environment irradiation test conditions，which indicates that the performance of the material can meet the reliability requirements of aerospace applications. According to the reserach results， technical guidance is provided for the aerospace application of LTCC substrate.