The deoxygenation of sulfoxides by HfCl4/NaBH4 system was investigated. The effect of reaction parameters, such as solvent, temperature, and molar ratio on the reduction was studied and discussed. According to the experimental result, when the solvent was tetrahydrofuran (THF) and the molar ratio of substrate/HfCl4/NaBH4 was 0.8/0.34/4.0, sulfoxides could be deoxygenated to sulfides in yields of 88%~99% by refluxing 0.6 h~1.5 h with HfCl4/NaBH4 system. Besides, in the oxygenation process，functional groups, such as -NO2, -OMe, -F, -Cl, and -Br groups were tolerated. This method was especially suitable for the deoxygenation of diphenyl sulfoxide and dibenzyl sulfoxide, and the yields were up to 98%~99%.