Abstract: Amorphous Ni-P catalyst was prepared by chemical reduction. Effects of initial solution pH and P/Ni molar ratio on the structure of amorphous Ni-P catalyst and the catalytic hydrogenation of nitrobenzene to aniline were investigated. Results showed that the initial solution pH and P/Ni molar ratio in the preparation process have great effects on the physicochemical properties of obtained amorphous Ni-P catalyst. Ni-P catalyst with amorphous structure was formed with high initial solution pH. With initial solution pH of 11.0，the amorphous Ni-P catalyst had a surface area of 13.7 m2/g with good thermal stability. When P/Ni molar ratio was less than 4，the amorphous phase content in the catalyst was low，and the optimum P/Ni molar ratio was 4. Using 0.2 g amorphous Ni-P catalyst，which was prepared with P/Ni molar ratio of 4 and initial solution pH of 11.0，for the catalytic hydrogenation of nitrobenzene，the conversion was 55.2% and the aniline yield was 53.8% after 3 h reaction.