Abstract: Combined temperature and humid environment experiment with damping property measurement technology, the experiment platform to test the damping properties of the embedded co-cured composite in heat and humidity environment was established. The new method using the least-square method was presented to analyze the relative damping coefficient. The effect curves of temperature, humidity and heat coupling parameters on damping coefficient of the embedded co-cured carbon fiber/bismaleimide composites were investigated respectively. The results show that the relative damping coefficient of the embedded co-cured composites is firstly enhancing and then decreasing lastly increasing with temperature increase. Under the effect of humidity and heat coupling environment, relative damping coefficient increases with humidity and temperature increase. The conclusion will lay a foundation for the design and application under all-weather environment of the new composite damping structure.