Nanocrystalline Cr-free Fe-Al-Cu catalysts with high surface area and mesoporous structure was prepared by coprecipitation method and employed in high temperature water gas shift reaction. Several parameters such as pH, aging temperature and aging time were optimized by the Taguchi method of experimental design. The sample prepared under optimized conditions showed a high surface area of 208 m(2) g(-1), pore size of 3.76 nm and theoretical particle size of 5.47 nm after calcination at 400 degrees C for 4 h. This catalyst illustrated the highest CO conversion compared to other prepared catalysts. These results confirmed that the Taguchi method is an effective method of determining the optimum parameters in preparation process of high temperature water gas shift catalyst. Moreover, the effect of calcination temperature, GHSV and steam/gas ratio on the catalytic performance of optimized Fe-Al-Cu catalyst was investigated. (C) 2015 Elsevier Ltd. All rights reserved.