Abstract: A supported catalyst for olefin polymerization, a preparation method and use thereof. The catalyst comprises a porous carrier A, a magnesium-containing carrier B, and a supported active component containing a transitional metal of titanium. The catalyst is a highly efficient Ziegler-Natta titanium-based catalyst having a composite support formed by a magnesium compound and a silicon compound, wherein the raw material for the magnesium compound may be any soluble magnesium salt. The supported catalyst may be used for preparing olefin homopolymers or olefin copolymers. According to the present invention, the molecular weight, molecular weight distribution of the olefin homopolymer or olefin copolymer as well as the contents and distribution of the comonomers may be adjusted conveniently by means of changing the factors such as types and amounts of organometallic co-catalyst and molecular weight regulator.