In aerospace structures，honeycomb panels were often connected with other components by clustered inserts.In order to analyze the reason for the failure of CFRP honeycomb sandwich panel under the effect of temperature stress， the theoretical calculation and finite element analysis of the failure stress were carried out.It was found that the instability of the panel caused the structural damage.To solve this problem，the feasibility and efficiency of two improvement measures of increasing the thickness of face sheet and local strengthening are analyzed.Through comparison experiment，it is found that the local reinforcement method is more feasible and efficient. Finally，through the thermal vacuum test，it is verified that the local reinforcement method can improve the stability of the panel and prevent the instability damage.