A process for synthesizing a catalyst component for manufacturing ethylene polymer and co-polymer. The present invention provides a process for synthesizing catalyst component (A), comprising forming a complex by contacting the solid intermediate (B) with an aluminum compound represented by formula X.sub.3-nAl(OY).sub.n, and alkyl metal (C), wherein X is halide, Y is a hydrocarbon group or chelating carbonyl group, and wherein 1 is less than or equal to n which is less than or equal to 3, and then contacting the complex with titanium halide having formula TiX.sub.4 wherein X is halide. Solid intermediate (B) is formed by reacting magnesium metal with alkyl halide in the presence of alkoxy aluminum represented by formula Al(OR.sup.a).sub.3, silicon halide represented by formula SiX.sub.4 and alkoxy silane represented by formula Si(OR.sup.b).sub.4, wherein R.sup.a and R.sup.b are an aromatic or aliphatic alkyl group and wherein X is halide. Alkyl metal (C) is synthesized by reacting alkyl aluminum compounds represented by formula AlR.sup.c.sub.3 with a secondary amine having formula HNR.sup.d.sub.2 and then by reacting with alkyl magnesium compounds represented by formula R.sup.eMgR.sup.f, wherein R.sup.c, R.sup.d, Re and R.sup.f are an aromatic or aliphatic alkyl group. The catalyst component is suitable for producing ethylene polymer and co-polymer with narrow molecular weight distribution as well as improved branching compositional distribution.