Abstract: With azobisisobutyronitrile(AIBN) as the initiator, a novel borate ester polymer surfactant(PBE) was prepared via the direct polymerization of N-hydroxymethyl acrylamide, triethyl borate and N,N-dihydroxyethyl dodecylamine. The structure of the compound was characterized by FTIR, ¹H NMR and GPC. Anti-hydrolysis ability, thermal stability(TG), emulsifying power of PBE and its borate ester monomer MBE were measured, and its surface properties at different pH values were studied by the surface tension method. The result shows by the direct polymerization synthesis process, white or light yellow powders PBE can be obtained with a yield of 77.2% after purification, and the product molecular weight M_w is about 28 400 g/mol. PBE possesses a good ability of anti-hydrolysis, and its thermolysis temperature may reach 320℃, the heat stability of which is better than that of MBE. The HLB value of PBE is in a range of 10~13, it has apparently better emulsifying power to paraffin oil, turpentine, toluene and benzine compared with MBE and commercial emulsification agent Tween-85. At 25℃, the critical micell concentration(CMC) of PBE in aqueous solution significantly decreased with pH increasing, when pH varied from 6 to 7, the CMC decrease extent was the greatest. However, the pH has little influence on the corresponding γ_CMC of PBE. At pH=7, 25℃, the CMC of PBE is 0.12 g/L, γ_CMC is 31.2 mN/m; surface activity of PBE is similar to those of regular low molecular weight surfactants, and is superior to those of certain polymeric surfactants, such as PVA and Pluronic104.