Method for preparing halogen-free flame retardant polyolefin material by utilizing multi-metal composite catalyst

The invention relates to a method for preparing a halogen-free flame retardant polyolefin material by utilizing a multi-metal composite catalyst. The method comprises the following step: carrying out melt blending on the multi-metal composite catalyst, solid acid and polyolefin to prepare the halogen-free flame retardant polyolefin material. The method is characterized in that the multi-metal composite catalyst is adopted as a main flame retardant, the solid acid takes a synergistic effect, and the polyolefin is catalyzed to form a compact carbon layer and insulates heat and oxygen, so that the flame retardant property of the polyolefin is improved. The method has the advantage that the charring efficiency of the multi-metal catalyst is higher than that of the single metal, the ratio of carbon residue when the multiple metals are combusted is 85%, and the carbon residue is 25%-30% when the single metal is combusted.