The purpose of this research is to provide the information and knowledge about the excellent co-solvent process to produce the high-purity biodiesel with minimum reaction time. Transesterification reaction of Jatropha oil with methanol in the presence of catalyst occurs in a heterogeneous system because the reactants are not readily miscible to each other. As a result, this leads to a longer reaction time and so higher fixed capital investment and product cost due to transesterification process is batch process. To speed up the reaction rate and to increase the fatty acid methyl ester yield, a mixing solvent tetrahydrofuran were added, which enables the reaction to be in one phase. The influence of various parameters on the transesterification reaction including the amount of THF, the amount of catalyst, methanol volume % and reaction time were investigated. Different tests according to ASTM methods were conducted to check the various properties of produced biodiesel and found according to ASTM D-6751.