A series of Mo-Zn-Al-O catalysts with different Zn/Al molar ratios were prepared. The structure of the catalysts was characterized using ICP-OES, zeta potential, XRD, BET, FTIR, H-2-TPR, O-2-TPD and ESR. The catalytic activity of these catalysts on the degradation of cationic red GTL wastewater under room condition was investigated. The experimental results showed that the highest color removal efficiency and TOC removal efficiency of cationic red GTL can reach 90.9% and 65.8% by the Mo-Zn-Al-O catalyst with 1:1 of Zn/Al molar ratio respectively. Associated with the characterization results of these catalysts. Mo-Zn-Al-O catalyst with 1:1 of Zn/Al molar ratio with highest catalytic activity could be contributed to its lowest zeta potential, largest specific surface area, special crystalline phases, special Mo valences, largest number of active adsorption sites and the maximum active species of O-1(2) or (OH)-O-center dot. The stable of these catalysts was also studied. Due to the lower leaching concentrations of Zn, Mo and Al, Mo-Zn-Al-O catalyst with Zn/AI molar ratio from 1:1 to 1:3 has a good stability. It is thought that Al3+ plays a more important part in determining the distance between metals, thus it affects the leaching of metals. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.