The superfine boron powder was coated by aggradation method with AP using methanol or acetone as the solvent. The coating effect were characterized by FT-IR, heat analysis, atom force microscope, transmission electron microscope et al, and the influencs on the coating of the solvent, vaporized velocity and amido-silicon alkyl were studied. The results show that the optimized vaporized velocity is 10 g·h^-1. The pretreatment of boron power by amido-silicon alkyl in advance brings a good coating effect of superfine boron powder.