Biodiesel produced from crude Jatropha curcas L. oil with trace sulfuric acid catalyst (0.02%-0.08% oil) was investigated at 135-184 degrees C. Both esterification and transesterification can be well carried out simultaneously. Factors affecting the process were investigated, which included the reaction temperature, reaction time, the molar ratio of alcohol to oil, catalyst amount, water content, free fatty acid (FFA) and fatty acid methyl ester (FAME) content. Under the conditions at 165 degrees C, 0.06% (by mass) H2SO4 of the oil mass, 1.6 MPa and 20 : 1 methanol/oil ratio, the yield of glycerol reached 84.8% in 2 hours. FFA and FAME showed positive effect on the transesterification in certain extent. The water mass content below 1.0% did not show a noticeable effect on transesterification. Reaction kinetics in the range of 155 degrees C to 175 degrees C was also measured.