Conjugated linoleic acid is a general term for a group of positional and spatial isomers of linoleic acid， among which the physiologically active isomers are cis-9， trans-11 and trans-10， cis-12 conjugated linoleic acid， which has rich nutritional and medicinal values. The isomerase of linoleic acid obtained by isolation and purification in Lactococcus spp. and Streptococcus spp. and other Lactobacillus， Propionibacterium and Rumen bacteria as well as other genera can catalyze the isomerization of linoleic acid to conjugated linoleic acid， and the synthesis of conjugated linoleic acid by enzymatic method can overcome the shortcomings of the traditional chemical synthesis method. This article has reviewed the recent research on the use of UV， microwave， plasma mutagenesis， ion injection and other physical or chemical methods to mutate and modify linoleic acid isomerase， optimize enzyme production conditions and enzymatic properties at home and abroad， and also described the related research on the use of targeted mutation， gene knockout and other genetic engineering methods to genetically modify the production strain and optimize the culture conditions to improve the yield of conjugated linoleic acid， so as to further screen the high yield. This study provides a theoretical basis for further screening of high-yielding conjugated linoleic acid strains and industrial application of conjugated linoleic acid.