Abstract: A supported metallocene catalyst includes a carrier and a metallocene component. The carrier includes an inorganic oxide particle and an alkyl aluminoxane material. The inorganic oxide particle includes at least one inorganic oxide compound selected from the group consisting of an oxide of Group 3A and an oxide of Group 4A. The alkyl aluminoxane material includes an alkyl aluminoxane compound and an alkyl aluminum compound that is present in amount ranging from greater than 0.01 wt % to less than 14 wt % base on 100 wt % of the alkyl aluminoxane material. The metallocene component is supported on the carrier, and includes one of a metallocene compound containing a metal from Group 3B, a metallocene compound containing a metal from Group 4B, and a combination thereof. A method for preparing the supported metallocene catalyst and a method for preparing polyolefin using the supported metallocene catalyst are also disclosed.