The invention provides a catalyst for olefin polymerization, which comprises reaction products of the following components: (1) a catalyst component which is formed by loading a titanium compound shown as a general formula (II) of Ti(ORw)4-kXk and at least two electron donor compounds a and b on alcohol adduct particles shown as a general formula (I) of MgC12.nRqOH; (2) an alkylaluminium compound; and (3) an external electron donor compound which is tetraalkoxide silane shown as a general formula (IV) of Si(ORx)4, wherein Rx represents C1 to C20 alkyl or naphthenic base or C6 to C10 aryl or aralkyl. The catalyst has high activity and high orientation capability. A polymer has wide molecular weight distribution. Meanwhile, the hydrogen regulation sensitivity of the catalyst is greatly improved.