The synthesis has been made on a new kind of phosphorus-containing compound 2-(phenylphosphoryl)-1,4-benzenediol, which is defined as PPBDO. Besides, it is utilized as a flame retardant and meanwhile a curing agent of epoxy resins (EP). The description of the chemical structure was made in virtue of Fourier transform infrared (FTIR) spectroscopy, 1H, together with 13C nuclear magnetic resonance. Investigation on the flame retardant properties, cured epoxy resins’ combusting performances, and thermal degradation behaviors in virtue of restricting oxygen index (LOI) and vertical burning tests (UL-94) as well as cone calorimeter and thermogravimetric analysis (TGA) experiments. According to the results from the cone tests, the PPBDO integration could efficiently decreased the combustion parameters featured by epoxy resins thermosets, including Heat release rate (HRR), Total heat release (THR), etc.. The TGA results displayed the PPBDO introduction managed to enhance epoxy resins matrix under the decomposition in advance, in comparison to the one pure EP, thus giving rise to a more concentration of char yield as well as thermal stability on the condition of high temperature.