Abstract: As the global installed capacity of wind power exceeds 561 million kilowatts, the large-scale disposal of waste wind turbine blades has become an urgent environmental and resource challenge. Focus is placed on the pyrolysis characteristics of glass fiber-reinforced epoxy resin composites, and the staged degradation patterns, product composition, and pyrolysis pathway of the main beam material of waste blades under a nitrogen atmosphere are systematically revealed via thermogravimetric analysis （TGA）, Py-GCMS detection, in-situ infrared spectroscopy, and kinetic modeling. Significant kinetic advantages are displayed by pyrolysis under nitrogen compared with the air atmosphere: the maximum weight loss rate is raised by 219%, and the interference of oxidative side reactions is eliminated. Dynamic variations are observed in activation energy alongside changing conversion rates: in the low conversion stage （α=0.1−0.6）, the reaction is dominated by the cleavage of the epoxy resin main chain with activation energy ranging from 99.7 kJ/mol to 141.9 kJ/mol, whereas in the medium-high conversion stage （α=0.6−1.0）, reaction progression is governed by a diffusion-reaction coupling mechanism corresponding to activation energy between 181.5 kJ/mol and 327.8 kJ/mol. In terms of pyrolysis products, organic constituents are mainly composed of bisphenol A （relative proportion 37.5%） and phenolic substances, and gaseous products are predominated by CO₂ （volume fraction 31.46%） and CH₄ （volume fraction 30.47%）. The pyrolysis pathway is centered on free radical reactions where preferential cleavage occurs at ether bonds and C—C bonds on benzene ring side chains: small-molecule nitrogen-containing fragments are released from fractured cross-linking bonds of amine curing agents at 200–300 ℃; epoxy resin main chains are ruptured to form intermediate products at 300–500 ℃; more thorough bond cleavage is realized above 500 ℃ alongside an elevated proportion of small-molecule products. A library of staged kinetic mechanism functions is constructed through collaborative analysis based on the Coats–Redfern and Criado models. Reaction behaviours are verified to fit specific kinetic models at different phases: the initial stage is matched with the nth-order reaction and nucleation-growth models （F1, A1/2）, the middle stage is governed by three-dimensional diffusion control （ZH model）, and the later stage is dominated by the condensation reaction interface （P3 model）. A multi-dimensional coupled pyrolysis kinetic analysis method is formulated by combining the global optimization capability of model-free methods, the mechanistic analysis superiority of model-based methods, as well as product and pyrolysis pathway characterization. Critical theoretical support is offered for follow-up resource-oriented recycling of waste wind turbine blades.