In order to study the high temperature degradation mechanism of acrylamide polymers in aqueous solution，two template polymers P （AA/AMPS） and P （AM/AA/AMPS） were prepared by using acrylamide （AM）， acrylic acid （AA） and 2-acrylamide-2-methylpropanesulfonic acid （AMPS） as monomers. The two polymers in aqueous solution were degraded at 200 ℃，220 ℃ and 240 ℃，respectively. The polymers and their degradation products were analyzed by FTIR，¹H NMR，XPS， GPC and TG-IR. The results showed that the high temperature degradation behavior of acrylamide polymers in aqueous solution mainly occurred in the side groups，which showed that the proportion of methylene in the main chain decreased. After the methylene bond was broken，the main chain was broken，resulting in the reduction of polymer molecular weight，and small molecules，such as carbon dioxide and ammonia，were generated in the degradation process. There is a contradiction between the temperature resistance of the two polymers in thermogravimetric test and that in aqueous solution. TG-DTG cannot be used as a standard to evaluate the temperature resistance of acrylamide drilling fluid treatment agent.