The invention relates to a Fe2-1.5xMoxS2-RGO hybrid catalyst and a preparation method and application thereof. According to the Fe2-1.5xMoxS2-RGO, nano particles are loaded on graphene oxide, then hydrothermal reaction is carried out, vulcanizing is carried out at high temperature and high pressure, and a part of the graphene oxide is reduced to generate the Fe2-1.5xMoxS2-RGO. The preparation method comprises the steps of the preparation of the graphene oxide and the preparation of the Fe2-1.5xMoxS2-RGO. Compared with the prior art, the cost of obtained Fe2-1.5xMoxS2-RGO hybrid catalyst is lower than that of an existing electrocatalyst, the hybrid catalyst can be used for electrocatalytic hydrogen evolution, doping of a Mo element reduces the over-potential in the electrocatalytic hydrogenevolution process, and the electrocatalytic hydrogen evolution effect is improved; and the stability of the catalyst is good, the preparation method is simple, the performance of the electrocatalytichydrogen evolution is enhanced, and the method can be used for industrial development.