Biodiesel made from vegetable or animal fats is a renewable substitute fuel for petroleum diesel. Continuous production of biodiesel fuel from soybean oil and methanol in an enforced mass transfer reactor without using any catalyst has been investigated. The effects of reaction temperature and molar ratio of methanol to soybean oil on the conversion of transesterification have been discussed. The optimal operational parameters were 360 degrees C and a molar ratio of 40 in this study. Transesterification of soybean oil could reach the expected conversion in shorter reaction time and lower pressure compared with the supercritical methanol method. The new process could reduce the investment cost of equipment. In addition, the apparent reaction order and activation energy of transesterification was 1.66 and 29.34 kJ/mol, respectively. Transesterification in an enforced mass transfer reactor could be a good alternative to the supercritical methanol method and could be more suitable for industrial production.