Polyacrylamide (PAM), as an important nitrogen-containing polymer material, is widely used in petroleum engineering, water treatment, and other fields. However, its thermal degradation behavior under high temperature conditions can lead to a decrease in solution viscosity and performance degradation. Traditional thermogravimetric analysis (TGA) is difficult to reveal the microscopic mechanism of chemical bond breakage and small molecule formation at the molecular level. Based on the ReaxFF reactive molecular dynamics method, this study constructed a simulation system containing 30 PAM molecular chains with a polymerization degree of 10, and investigated the pyrolysis process and reaction kinetics characteristics of PAM at high temperatures. Arrhenius fitting revealed that the overall activation energy of PAM pyrolysis is 116.4 kJ·mol?1, while the dissociation activation energies of the C-N and N-H bonds in the amide groups are 129.2 and 132.3 kJ·mol?1, respectively. For the platform-like intermediates, the degradation activation energies of C30 and N10 species were calculated to be 143.6 and 126.4 kJ·mol?1, respectively. These results confirm that the early decomposition of PAM follows a “preferential amide bond cleavage with de-nitrogenation preceding de-oxygenation” pathway. Mechanistic analysis further revealed that NH3 is mainly produced through intra-/inter-molecular imidization and radical hydrogen abstraction, N2 is generated via NH2 radicals attacking C=N groups followed by hydrogen migration and bond cleavage, while H2O originates from the hydrogenation of O=C-containing radicals and subsequent C-O bond scission. This study not only elucidates the molecular-level evolution sequence of PAM pyrolysis products but also complements experimental findings by providing bond-scale kinetic insights. The ReaxFF-based strategy demonstrates broad applicability in exploring the pyrolysis mechanisms of nitrogen-containing polymers and offers theoretical guidance for designing controllable thermal decomposition processes and novel materials.