The invention discloses a carrierized back-transtion metal catalyst, and calculated according to the weight share, it is composed of the following components and content; back-transmition metal alkene polymeric catalyst I 0.05-0.5; aluminum alkyl or oxygen-aluminium alkyl alkane 1.75-40; inert carrier 100. The invention also discloses the preparing method and the application in catalyzing the polymerization of ethylene. The invention, the carrier back-transition metal catalyst and the assistant catalysts, such as oxygen-aluminum alkyl alkane, aluminium alkyl, etc. make up the system of catalyst to catalyze the polymerization of ethane.