A self- made phosphorus containing diol P- 2OH was synthesized from phenyldichlorophosphate, triethylamine, hydroxyethyl methacrylate, 2 - (diethylamino) ethanol and diethanolamine. Using isophorone diisocyanate (IPDI), polycarbonate diol (PCDL), hydroxyl terminated polysiloxane (PDMS), phosphorus containing diol(P- 2OH), dihydroxymethylpropionic acid (DMPA), pentaerythritol triacrylate (PETA) ,a waterborne UV curable six arm polyurethane modified by phosphorus and silicon was synthesized by dipentaerythritol (Di- PE) and triethylamine. The synthesis of the polymer was characterized by IR and NMR. Compared with pure WPU, when the mass fraction of phosphorus containing diol is 21.1% and the content of hydroxyl terminated polydimethylsiloxane is 12.1%, the comprehensive performance of the film is the best. Its water resistance is enhanced, the limiting oxygen index (LOI) is increased from 17.8% to 27.5%, UL-94 grade reaches V-0 grade, the graphitization degree of residual carbon is improved, and the flame retardant performance are improved.