The present invention relates to a high-effective solid catalyst for producing theoretical density polyethylene by slurry polymerization. It is characterized by that the commerically available magresium dust is used as initiation raw material to prepare nascent state magnesium halide, then the magnesium halide is reacted with organic alcohol and alkylaluminium one after another to obtain solid suspension, and in the presence of electron donor and alkylaluminium, the obtained solid suspension and transition metal halide are reacted to obtain the main body component of said catalyst, then the main body component and catalyst promotor organic metal compound are together formed into the invented polyethylene high-effective catalyst. Said catalyst possesses the advantages of simple preparation, high polymerization activity, sensitive hydrogen regulation, stable reaction and good product form, etc.