Using patented nature carboxylate and its modification as the major surfactant, we obtained compounded nonionic surfactant by the interaction parameter βm. Then we measured the pseudo ternary phase diagram of compounded surfactants/water/diesel oil, from which got three cheap and efficient diesel oil emulsifier. The emulsifier includes little flame accelerator,cetane improver and smoke suppressor. Through the bench test, we found that the average rate of economizing petrol was 20 % and the emissions of NOx dropped to 20 %. And every ton of emulsified diesel oil can save 500 yuan around.