Abstract: A method of reactive extrusion copolymerization of vinyl monomer consisting of (1) feeding vinyl monomer or at least one vinyl monomer together with an initiator into the first screw of twin-screw extruder, and modified resin into the subsequent screw section; (2) feeding the above monomer into the screw segment after auto-acceleration zone and feeding the initiator corresponding to the temperature of barrel and micro/nano inorganic modified fillers after the half-life period of the initiator; (3) feeding the antioxidant and anti-UV agent at the end of the polymerization, and then removing unpolymerized monomer and by-products by devolatilization of screw segment; (4) obtaining vinyl copolymer resin with a anticipated molecular weight of 5×102 to 6×105 from the reactive extrusion polymerization by controlling the temperature of different screw segments.