Abstract: In order to analyze the catalytic performances of the nickel based catalyst to the methanation reaction of the synthetic gas, with the La2O3 modified high ratio superficial area y-AI2O3 as the carrier, the isochoric immersion method was applied to prepare the methanation catalyst of the synthetic gas and investigate the po re structure properties, the reduction performances and the reaction performances of the nickel based catalyst.The results showed that the modified carrier could directl y load the activated component nickel, the CO conversion rate could be 58% and the selectivity of methane could be 70%. Based on the modified carrier, the reaction pe rformances of the joint immersion manganese assistant and the activated component nickel could be further improved.The CO conversion rate could be improved to 7 2% and the selectivity of methane could be improved to 75%.