H3BO3 promotes the removing oxygen-containing functional groups of epoxy resin (EP) and forms B-O-C bond with EP. The char yield of EP increases first and then decreases with H3BO3 content increasing, which is 33.4 wt% and 19 wt% for 9 wt% H3BO3 modified EP and EP. The graphitization degree (g) and grain stacking thickness (Lc) of EP carbon foam (CF) first decrease and then increase with H3BO3 increase. The graphitization degree (g) of 3, 6, 9 and 12 wt% H3BO3 modified EP CF are 11.6, 0, 0, and 23.2%. The ID/IG value of 0, 3, 6, 9, 12 wt% H3BO3 modified EP CF are 0.97, 1.05, 1, 1.1, and 0.89. For low H3BO3 content (0, 3 wt%), the small bubbles combined easily, and led to bigger bubble size. When the H3BO3 content was high (above 6 wt%), the combination of small bubbles becomes more difficult, and decreases cell size. The cell sizes of 0, 6, 12 wt% H3BO3 modified EP CF are 620 µm, 440 µm, 760 µm, respectively. When the H3BO3 varies from 0 and 3 wt%, the electrical conductivity of modified EP CF increased from 15.56 to 25.94 S/m. The compressive strength of the H3BO3 modified EP CF gradually decreased with increase of H3BO3 from 0 to 12 wt%, which can be influenced by its density. The compressive strength of 12 wt% H3BO3 modified EP CF is only 0.6 Mpa, which is much lower than the EP CF (3.32 MPa).