The invention relates to a supported non-metallocene catalyst and a preparation method. The supported non-metallocene catalyst is prepared by the steps of precipitating a magnesium compound slurry containing a non-metallocene ligand and a porous carrier, and treating with an IVB group chemical treating agent; the preparation method is simple and feasible, the load capacity of the non-metallocene ligand is adjustable, and the combination of each compound in the catalyst is close. The invention also relates to the application of the supported non-metallocene catalyst in olefin homopolymerisation/copolymerization. Compared with the prior art, the supported non-metallocene catalyst has the characteristics of less usage of a cocatalyst for catalyzing polymerization of alkene, high polymerization activity, substantial copolymerization effect, high bulk density of polymer, narrow molecular weight distribution, and high and adjustable viscosity average molecular weight of the prepared ultrahigh molecular weight polyethylene.