The invention discloses a method for preparing a catalyst for hydrogenating a pyridine compound. The method comprises the following steps of: 1, pre-treating activated carbon; 2, preparing a precursor solution; 3, immersing the activated carbon by the precursor solution; 4, reducing, washing and drying to obtain the catalyst. The invention also discloses another method for preparing the catalyst for hydrogenating a pyridine compound, which comprises the following steps of: 1, pre-treating alumina; 2, preparing a precursor solution; 3, immersing the alumina by the precursor solution, drying, roasting and reducing to obtain the catalyst. According to the catalyst prepared by the invention, the activated carbon or activated alumina is used as a carrier, noble metal ruthenium and auxiliary metal element are loaded and highly dispersed on the carrier, and the granularity of ruthenium metal particles in the catalyst is 30nm-80nm. The prepared catalyst is suitable for catalytically hydrogenating pyridine compounds to synthesize piperidine compounds, the conversion rate of the catalytic hydrogenation reaction is high, and the production cost for the piperidine compounds can be greatly reduced.