Fat transesterification is the transesterification of fats and oils. Oil transesterification refers to the transesterification or molecular rearrangement process caused by the interaction between triglycerides in oil and fatty acids, alcohols themselves or other esters. Through transesterification reaction, the composition, structure and properties of glyceryl esters in oils can be changed to produce natural oils with new structures, or some natural oils that people want to obtain to meet certain needs. It can also produce monoglycerides, diglycerides and other esters besides glycerides. Transesterification, hydrogenation and fractionation are the three basic processes of petroleum modification.