Abstract: Phloroglucin tri(diphenyl phosphate) was synthesized based on phloroglucin, phosphorus oxychloride, and phenol. the optimal reaction conditions were as following:using aluminum chloride as a catalyst, molar ratio of phloroglucin to phosphorus oxychloride was 1:5，reacted for 7 h at 70℃，followed by 8 h at 130℃.A gross yield of 87.2%was obtained. A mixture of the product andmelamine ( mass ratio 3:1)was introduced into epoxy resin (mass ratio of epoxy/mixture=85/15)，the limiting oxygen index and UL94 of the latter became 32. 2%and V-0，respectively.

Key words: phosphorous flame retardant, phloroglucin, phloroglucin tri(diphenyl phosphate), epoxy resin