The maximum quality change rate and maximum corrosion current density in the simulated seawater were1.31×10-2 mg×cm-2 × d-1 and 1.058×10-5 A/cm2, respectively, which can be thought little and almost had no any virtual damage on the structure and composition B4C composite ceramic. In addition, the corrosion product was so small that cannot be detected by XRD, and this conclusion can be got by the comparison between Fig. 7 and Fig. 11, so we can think that B4C composite ceramic had excellent corrosion resistance in simulated seawater.