A new technique for extraction of NA from crude oil with high TAN was proposed. Petroleum acids in crude oil with high total acid number were extracted by a complex solvent. Optimum constituents of the complex solvent are A 5%, B 8%, C 40% and D 0.5%～1% by weight, and optimum ratio of solvent to oil is 0.15. The results indicate that more than 80% of the petroleum acids is removed, the purity of NA is high enough to be used in industry and the process has no environmental pollution because all of the solvent are recoverd and reused in the unit.