Abstract: The temperature-humidity-vibration combined environmental tests are carried out for the spacecraft avionics. By detecting the defects of the products, the reliability of equipment can be improved through these tests. This paper mainly analyzes the failure modes and their mechanisms for the spacecraft avionics under combined environments, and discusses the test design, the process control methods, and several other issues related to the combined environmental tests for the spacecraft avionics, as well as the test development direction. It provides a reference for further promotion of the temperature-humidity-vibration combined environmental tests.