The present invention provides a high-activity solid main catalyst component for ethylene polymerization, a process for preparing the same and a catalyst containing the same. The main catalyst component consists essentially of a magnesium compound, a titanium compound, an electron donor, an alkyl aluminum compound and fumed silica, and is prepared by a process comprising the step of: reacting powdered magnesium with an alkyl halide to form a magnesium compound in the nascent state; adding the magnesium compound in the nascent state together with a titanium compound and an alkyl aluminum compound into an electron donor to form a complex; adding and well dispersing a fumed silica thereto to form a homogeneous thick mixture; molding and drying the mixture to form main catalyst component particles with good particle morphology; and optionally, dispersing the main catalyst component particles into a hydrocarbon solvent or a mineral oil to form a slurry. The main catalyst component has high magnesium/titanium ratio, high titanium content, high polymerization activity, moderate initial activity so that polymerization can be stably performed, and there is little or no agglomerates during the preparation of the main catalyst component.