Bending properties and failure modes of carbon fiber composite egg and pyramidal honeycomb beams were studied and presented in this paper. Three point bending responses of both sandwich beams were tested. Face wrinkling, face crushing, core member crushing and debonding were considered, and theoretical relationships for predicting the failure load associated with each mode were presented under three point bending load. Failure mechanism maps were constructed to predict the failure of composite sandwich beams with pyramidal and egg honeycomb cores subjected to bending. Face wrinkling and core debonding have been investigated under three point bending and the maximum displacement was studied using analytical and experimental methods. The finite element method was employed to determine the ratio (maximum displacement/applied load) of sandwich beam with two different honeycomb cores. Comparisons between two kinds of honeycomb beams were also conducted.Fil: Xiong, Jian. Harbin Institute of Technology. Center for Composite Materials and Structures; ChinaFil: Ma, Li. Harbin Institute of Technology. Center for Composite Materials and Structures; ChinaFil: Stocchi, Ariel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigación En Ciencia y Tecnología de Materiales (i); ArgentinaFil: Yang, Jinshui. Harbin Institute of Technology. Center for Composite Materials and Structures; ChinaFil: Wu, Linzhi. Harbin Institute of Technology. Center for Composite Materials and Structures; ChinaFil: Pan, Shidong. Harbin Institute of Technology; China