The synthesis of 1,3,2-Dioxathiane 2,2-dioxide was accomplished by 1, 3-propanediol and thionyl chloride as raw materials, potassium periodate as oxidant，using ruthenium(III) chloride as catalyst. The product was characterized by IR and HNMR spectra. The effects of reaction temperature, reaction time, molar ratio of raw material, oxidant species, the amount of catalyst and oxidant on the yield of target product were investigated. The optimal condition was determined as follows: at 40 oC for 60 min, 1,3-propanediol 60 mmol, n(thionyl chloride):n(1,3-propanediol)=1.2:1, m(catalyst):m(1,3-propanediol)=0.0015, m(potassium periodate):m(1,3-propanediol)=0.3:1. The yield of the product could reach 92.75%.