Combined with the heat transfer mechanism of honeycomb structure and the ablation mechanism of composites, the thermal response of honeycomb sandwich composite structure under laser irradiation was studied. For typical honeycomb cells, a theoretical microstructure model of thermal conduction and ablation is established. Based on the finite element software thermal analysis module and secondary development program, a high temperature heat transfer numerical model of honeycomb sandwich structure was constructed, taking into account the nonlinear changes of thermal physical parameters, resin pyrolysis and fiber ablation process. Using continuous laser as the loading heat source, the thermal ablation experiments of honeycomb structure in atmospheric environment were designed and carried out, and the dynamic ablation characteristics of honeycomb structure were obtained. The results show that the honeycomb sandwich composite structure has good ablation resistance when the laser power density is 10² W/cm²; The numerical model can accurately simulate the temperature field and the ablation of resin and fiber in the process of laser loading the honeycomb structure, and can obtain comparatively real ablation morphology.