Vapor phase hydrogenolysis of diethyl maleate on Cu-Zn-Al-O catalysts is investigated for the coproduction of 1,4-butanediol, gamma-butyrolactone, and tetrahydrofuran. Roles of catalyst composition are explored and a high (Cu + Zn)/Al ratio is found necessary for a high yield of 1,4-butanediol. The catalyst calcination and reduction procedures are characterized by X-ray diffraction (XRD) and thermal analysis techniques. The preliminary results show that two active sites, associated with Cu-0 and Cu+ phases, respectively, may exist on the catalyst with the former responsible for the formation of tetrahydrofuran and the latter for 1,4-butanediol and gamma-butyrolactone. The optimum operation conditions for the production of 1,4-butanediol as the main product are recommended as 473 K, 4 MPa, 0.2 mL (diethyl maleate)(g of catalyst)(-1) h(-1) and 100/1 (H-2-diethyl maleate), under which 1,4-butanediol yield reaches 59%, gamma-butyrolactone 26%, and tetrahydrofuran 15%. Furthermore, the stability of the catalyst is tested over 200 h and the poisoning effect of sulfur in feed is demonstrated to cause only the decline of catalyst activity but not product selectivity.