The each compounds of TCPP(Tri(2-chloropropyl) phosphante), TCEP(Tri(2-chloroethyl) phosphate), TMP(trimethyl phosphate) and TEP(triethyl phosphate) has been reacted with flexible polyurethane scrap to convert into liquid forms by thermal degradation. The structure, OH-value, and viscosity of the degraded products(DEP) were studied by FT-IR, titration and viscometer. The DEPs from flexible polyurethane scrap were apply as flame retardant to synthesize the rigid polyurethane foam. The thermal stability and inflammability of rigid polyurethane foams were extimated.