A catalyst component for ethylene polymerization, including an inorganic oxide support, and at least one alkyl metal compound, at least one halide, at least one dihydrocarbyl magnesium compound, at least one difunctional compound that reacts with the dihydrocarbyl magnesium compound and at least one titanium compound, wherein the difunctional compound is a mono-, di- or multi-halogenated alcohol or phenol having from 2 to 20 carbon atoms; or a mono-, di- or multi-halogenated acyl halide having from 2 to 20 carbon atoms. Also, a process for preparing the catalyst component and use thereof.