The invention relates to a supported catalyst for hydrosilylation and a preparation method thereof. The technical problem to be solved by the invention is to provide a multi-phase catalyst, namely the supported catalyst for hydrosilylation, for the hydrosilylation of an olefin and a hydrogen-containing silane, and a preparation method thereof. When the catalyst is used, the reaction conditions are mild, safety and effective, and the catalyst can be separated from the product conveniently and can be recycled. The catalyst is a supported Pt catalyst having a structural formula below. The preparation method comprises the following steps: 1) modifying the surface of the inorganic carrier by using coupling agent; 2) modifying the surface of the carrier by using a functional group-containing compound; and 3) coordinating and complexing with chloroplatinic acid to obtain the supported Pt catalyst.