The present invention provides a novel dual-function lipase mutant and its application in processing of flour products. The amino acid sequence of the lipase has one of the following amino acid substitutions: P298T,P298T/H317P, P298T/H317P/V326S, P298T/T218S/S234F, P298T/H317P/P168L/A129S, P298T/S234F/K161R/V326S, wherein the substitutions are relative to a parent amino acid sequence set forth in SEQ ID NO:1; wherein the lipase mutant maintains a triglyceride and lecithin hydrolysis activity and good performance in thermostability. The mutants have good performance in processing of flour products, while they can significantly whiten the bread or other products in processing of flour products and significantly increase the specific volume in bread baking process.