Abstract: Alcohol dehydrogenase, lactate dehydrogenase and NAD were immobilized separately and coimmobilized site-to-site on p-aminobenzenesulfonylethyl-CL sepharose activated previously with glutaraldehyde. The regeneration ability of NAD with the coimmobilized tribasic enzyme system obtained here was five times as high as that with the corresponding free enzyme system. And finally, the coimmobilization process and NAD regeneration ability of the tribasic enzyme system were discussed.