Tetraethylorthosilicate (TEOS) and methyl trimethoxysilane (MTMS) were used as raw materials to prepare an Ru-silica aerogel catalyst by sol-gel and the supercritical drying method. The catalyst was characterized by various techniques including BET, TEM, FTIR, SEM, XPS, XRD, TG, and EDS. It was used for the hydrogenation of p-phenylenediamine (PDA) to 1,4-cyclohexanediamine (CHDA). The effect of various parameters, such as loading methods, catalyst components, catalyst amount, and the reaction time were systematically investigated. It was found by XPS that supercritical ethanol can convert Ru3+ to Ru-0 by its strong reducing property. The catalyst prepared by sol-gel and the supercritical drying method is homogeneous, with high loading rates and a high specific surface area above 700 m(2)/g. The reactivity of the catalyst prepared by the sol-gel method is much higher than that prepared by the impregnation method. The PDA conversion of 99 % alone with the CHDA selectivity of 64 % were achieved under the reaction temperature of 150 degrees C and the pressure of 5 Mpa for 1 h. The PDA conversion decreased as the MTMS ratio increased in the catalyst. The anti-cis ratio of CHDA reached the maximum value (2.25) when the ratio of MTMS/ TEOS was 2/3.