Molecular weight of polyacrylamide is one of the main factors affecting its properties. In order to increase molecular weight of polyacrylamide, an experiment study on the course of polymerization generation of polyacrylamide is conducted. Using refined acrylamide, sodium carbonate and water as main raw, by method of anterior alkaline cohydrolysis polymerization. This experiment analyzes the influence rule of initial reaction temperature, the dosage of chelator EDTA-2Na, hydrolysis time on the high Molecular weight of polyacrylamide, and confirms the synthetic conditions of high molecular weight of polyacrylamide. The results obtained provide the basis for the industrial production of polyacrylamide.