SPDPC was synthesized in Ion Liquid as solvent and catalyst. Pentaerythritol reacted with phosphorus oxychloride in 1:2.2 molar ratio under 40℃ for 7h,the yield is 66%. The structure of SPDPC was characterized by MP, IR and 1HNMR. The catalytic mechanism of Ion Liquid was speculated. The new way was compared with the traditional ones. It is found that Ion Liquid as solvent and catalyst not only shortened the time of reaction and reduced the reactive temperature, but avoided volatilizing, more collectable, economical and environmental friendly as a suitable solvent and catalyst for SPDPC synthesis.