Biodiesel, an diesel alternative fuel. has attracted much attention because of its environmental benefits and renewability. Several transesterafication methods can be used to produce biodiesel, such as, homogeneous acid/base catalysis, lipase-catalyzed reaction, supercritical method and solid acid/base catalysis. However each method has its advantages and disadvantages. Homogeneous acid/base catalysis is very fast and with high efficiency, but down-stream product is difficult to purify and with significant pollution; Lipase-catalyzed reaction can take place in mild conditions and do not need excess methanol. It is not sensitive to water and free fatty acids, and the down-stream process is easy. But Lipase is too expensive which blocks its commercial use. Supercritical method is a new technology that is fast, and do not need catalyst. It has high conversion efficiency, but it requires high temperature and high pressure, and so high energy consumption, therefore is not cost effective. Solid acid/base catalyst, which can be recycled, has less causticity and without pollution. The down-stream product is easy to separate, which has less impaction on the environment. Supported solid base catalysis will be the main trend for biodiesel preparation by transesterification.