The invention relates to a method for preparing adrenaline. According to the method, a substrate undergoes reduction reaction in the presence of a ketoreductase, a coenzyme and a coenzyme regeneration system so as to produce adrenaline, wherein the coenzyme regeneration system comprises glucose and glucose dehydrogenase, the reduction reaction is carried out in a buffer solution with the pH value of 5-7, and the reaction temperature is 0-15 DEG C. According to the method, adrenaline is prepared from the ortho-position dihydroxyl-protected substrate by using a ketoreductase one pot-method, thus, efficient asymmetric enzyme reduction is realized, and then, the pH value is adjusted so as to remove protecting groups through hydrolysis; compared with the existing chemical resolution methods or chemical metal asymmetric synthesis methods, the yield and optical purity are higher, and the cost is lower.