Abstract: A novel PEPA-based halogen-free organic phosphorus flame-retardant-bis(2,6,7-trioxa-1-phosphabicyclo2.2.2 octane-4-methanol) methyl phosphate (PTC) was prepared through a three-step reaction from starting material phosphorus oxychloride, pentaerythritol and methyl alcohol. Intermediate product (Ⅰ) was prepared in 86% yield by the reaction of pentaerythritol with phosphorus oxychloride in the media of diethylene dioxide. The condensation of compound (Ⅰ) with phosphorus oxychloride in acetonitrile media gave intermediate product(Ⅱ) in 78% yield. The title compound PTC was synthesized from compound(Ⅱ) and methyl alcohol with yield of 69.1%. The melting point of PTC was 264℃~265℃. The main influence factors of the formation of the target compound PTC were discussed. The structure of the PTC had been determined by infrared spectroscopy (FT-IR), nuclear magnetic resonance(¹H NMR) and liquid chromatography mass spectra (LC-MS). PTC has good thermal stability and char formation tested by thermogravimetric analysis (TGA).