The glass fabric was coated by the epoxy resin glue filed with the shell powder that surface-treated by KH560 coupling agent, and then heat compressed and solidified to prepare the epoxy resin based composites. The stability and dispersion of the shell powder in the glue, and glue gelation time, the interfacial morphology, mechanical performances and electric properties were investigated by polarizing microscope, SEM, high resistance meter, resistance to tracking index tester. The results showed that both the reduction of the particle size and surface modification were advantageous to prolong the settlement time of the shell powder in glue, and the latter was obvious to improve the dispersion. The polar groups in shell powder can participate in the solidification reaction of epoxy resin, thus inserting the crosslinking net of the thermal set resin, which effectively improve the interfacial combination and enhance the mechanical performances. On the other hand, the electric insulativity of the shell powder filled system was well maintained. Accordingly, the composites showed promise by serving as insulation materials. Financial supports from Xiamen Southern Oceanographic Center (14GZP004NF04, 14GQT61HJ31), Marine high-tech industry development project of Fujian Province, China (marine high-tech [2015]15), Science and Technology Planning Project of Fujian Province, China（2015Y0034）and Public science and technology research funds projects of ocean(No.201505029).