By using heteropoly acid/acetone system as chemical extr ac tant, a novel process was developed to selectively remove nitrogen-containing c ompounds from lubricating oil base stocks. The results showed that the process could effectively reduce the content of nitrogen-containing compounds and thus greatly increase the anti-oxidative stability of the lubricating oil base stock s, without significantly lowering sulfur content and affecting other physical an d chemical properties of the refined base stocks. This work may provide an alte rnative way for denitrification of lubricating oil base stocks.