The invention discloses a methanol synthesis catalyst precursor, a methanol synthesis catalyst, and preparation methods of the methanol synthesis catalyst precursor and the methanol synthesis catalyst, wherein the methanol synthesis catalyst precursor comprises the hydroxides of Cu, Zn and Al, and the particle size distribution (calculated as the volume fraction) of the methanol synthesis catalyst precursor is that the particles having a particle size of less than 20 [mu]m account for less than 15%, the particles having a particle size of 20-50 [mu]m account for 60-85%, and the particles having a particle size of more than 50 [mu]m account for less than 30%. According to the present invention, with the application of the catalyst prepared from the methanol synthesis catalyst precursor in the methanol synthesis process, the advantages of high activity, high selectivity and high stability are provided.