The pyrolysis kinetics of silicone rubber insulators (SiR) in nitrogen (N₂) and air environments were studied by thermogravimetric analysis (TGA). Three transformation models, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Friedman (FR) methods, were applied to calculate activation energy and pre-exponential factors. The average activation energies of FWO, KAS, and FR methods under N₂ atmosphereare were 421.46, 431.60, 433.98 kJ/mol, respectively. The pre-exponential factor ranged from 10⁹ to 10¹⁶, which illustrated that the pyrolysis was independent of surface area. Under the air atmosphere, the average activation energies of FWO, KAS, and FR methods were 127.21, 120.93, 123.38 kJ/mol, respectively. The value of pre-exponential factor ranged from 10⁸ to 10⁹, and pyrolysis was controlled by surface area. The thermodynamic properties of the reaction under N₂ atmosphere, such as enthalpy changes (ΔH), Gibbs free energy (ΔG) and entropy change (ΔS) were much higher than that under air atmosphere, confirming the complexity of the reaction in N₂. The results of the study contribute to a deeper understanding of the combustion mechanism of SiR and provide a reference for its feasibility as a more effective high-temperature resistant material.