The invention discloses a polyethylene catalyst and its preparation method. It is characterized by that it makes two carriers into different surface structures be reacted with titanium compound, and adopts a still ball-milling process to make preparation so as to obtain the load-type catalyst with several activity centres. The catalyst prepared by using said method is low in cost and small in environmental pollution, and its property is stable, said catalyst can be applicable to several polymerization processes, and the regulation of the mixing ratio of two carriers and polymerization technological parameters can be utilized so as to can obtain the polyethylene with wide molecular weight distribution whose Mw/Mn is above 7, and its molecular weight distribution can be regulated.