Catalyst Cu/ZnO/Al2O3 was prepared through co-precipitation method and investigated in a stirred slurry autoclave reactor system for methanol synthesis. The structure of the catalysts was studied by derivative thermogravimetry (DTG), X-ray diffraction (XRD) and H-2 temperature programmed reduction (H-2-TPR). The results show that the average size of CuO crystallite of the catalyst was 3.23 nm when the catalyst was calcined at 623 K for 2.0 h, and the catalyst with this size of CuO crystallite is highly active and stable. Its space time yield and deactivation rate reached 172.2 g/kg(cat).h and 0.43%/d, respectively under the reaction conditions of 513 K, 4.0 MPa, H-2/CO/CO2 = 68/24/5 and space velocity = 810 ml/g(cat).h. (C) 2009 Elsevier Ltd. All rights reserved.