The composite honeycomb sandwich structure is widely used in aerospace, automobile transportation and other engineering fields because of its high energy absorption capacity and high specific strength. Taking the “Y” shape structure as the analysis object, the equivalent in-plane and out-of-plane mechanical property parameters of the honeycomb core were analyzed through theoretical analysis. The equivalent property parameters of the glue layer were obtained by numerical simulation analysis. The numerical simulation analysis of the low-velocity impact to the honeycomb sandwich structure of the composite material was carried out, and the results were relatively consistent with the experimental results. The impact effect of the two anti-impact design schemes of adding glass cloth and changing the original stacking sequence is studied, and the optimal design scheme of anti-impact of the composite honeycomb sandwich structure is determined.