The invention provides microblock polyacrylamide. Microblock polyacrylamide comprises an alkyl chain hydrophobic group with a hydrophobic function. A synthesis method of the microblock polyacrylamidecomprises the steps that 1, a hydrophobic monomer octadecyl acrylate is prepared through an esterification reaction; 2, in a redox initiation system, by adding OP-10 and a cosolvent sodium alcohol ether sulphate, the hydrophobic monomer octadecyl acrylate is grafted onto a polyacrylamide chain by means of a micellar copolymerization method to form microblock polyacrylamide. By means of the method,the temperature and salt resistance of polymer is improved, obtained microblock polyacrylamide is not sensitive to sewage, the stable high viscosity can be kept without adding a stabilizer during use, and microblock polyacrylamide is worthy of application and popularization.