Step-by-step scale-up synthesis of comb-copolymer PMAS was carried out using acrylamide （AM）， allyl polyoxyethylene ether （APEG），docosyl acrylate （DA） and 2-acrylamido-2-methylpropanesulfonic acid （AMPS） as reaction monomers，azodiisobutyronitrile（AIBN）as initiator and sodium dodecyl sulfate（SDS）as surfactant via a free radical micellar polymerization，and the properties of viscosity increment，temperature resistance，salt resistance and shear resistance were evaluated，the viscosity increasing of PMAS in the drilling fluid before and after hot-rolling was evaluated. The results showed that the scale-up experimentation of PMAS exhibited slightly varying properties when prepared by three different polymerization scale， however，always maintained excellent viscosity increments，temperature，salt resistance and shear-tolerance. After aging at the temperature of 190 ℃ for 16 h，the apparent viscosity retention rates of low-salt and saturated brine drilling fluids with 1% PMAS were 61.4% and 60.0%，respectively. The temperature and salt resistance of PMAS at big polymerization scale was superior to that of the commercial viscosifier 80A-51，exhibiting a good application prospect.