The Practical Research of BiodieselXU Yuan-hao,YE Sheng-yan,CHEN Zhong-xiang,LIU Bo (School of Automotive Engineering, Wuhan University of Technolo gy, Wuhan 430070, China)This article introduces how to make biodiesel fuel from vegetable oil and methan ol with catalyzing sodium hydroxide by transesterification. Different kinds of f actors, which influence the last reactive ration, were analyzed. The best three conditions were concluded which including mass of sodium hydroxide should be one percent of the vegetable oil, the reactive time should be 40 to 50 minutes, the molar ratio of vegetable oil and methanol should be one to six. Under these con ditions, last reactive ration can reach eighty seven percent. Many studies have shown that the physicochemical characteristics of biodiesel and conventional die sel oil were similar. It could be applied to diesel engines directly without mod ifying it. When the blended fuel in diesel oil is blended with biodiesel of diff erent rations are used on diesel engine, the emission of CO, HC and soot reduced greatly. While the emission of NO x increased a little, the rate of oil co nsumption hardly changed and no significant change had been found in the engine' s performance.transesterification; biodiesel; blended fuel; emission