Swida wilsoniana oil is one of the raw materials of biodiesel,which has an important significance to alleviate the pressure on the raw materials for biodiesel production.The fatty acid in S.wilsoniana oil,physicochemical properties and properties of biological diesel oil were determined.The results demonstrated that the accumulation of palmitic acid and oleic acid occurred mainly on the early stage of fruit development,and the content of linoleic acid was increased much in later development period.In the whole course of the fruit development,the stearic acid content was found to be continuously decreased and finally tend to a stable value at 2%; Unsaturated fatty acid(UFA)was increased and the trends of saturated fatty acid(SFA)accumulation was decreased,wheras the change was relatively stable; It was also found that pre-esterifies reaction in the production of biodiesel which could avoide the excessive use of drugs was necessary,besides,low and moderate iodine value and saponification value was favorable for reducing production cost; The content of UFA and SFA in mature fruit oil was lower than the common edible oil but higher than other raw materials of biodiesel,that was up to 70.28%and 22.39%,respectively.Moreover,the higher content of C18 may have contributed to saving of some chemical process steps; The biodiesel produced by S.wilsoniana oil are low density,low viscosity and high cetane ratio compare with Jatropha curcas and Sapium sebiferum which was similar to 0# diesel.The flash point of S.wilsoniana oil was lower than Jatropha curcas and Sapium sebiferum,particularly the ash content,that was only 0.003%.