Microwave-assisted pyrolysis is the preferred technology for enhancing the production of fuels and valuable chemicals. Therefore, pyrolysis experiments of furfural residue (FR) were performed using microwave equipment without microwave-absorbing additives. Further, to explore the interactions and intrinsic mechanisms of biomass components, thermogravimetric (TG), kinetic calculation, Py-GC/MS and TG-MS were also employed. Results showed that the temperatures and catalysts both affect the yields and compositions of products. Moreover, kinetic calculations showed a high-level consistency between FR pyrolysis and P3 mechanism. The product analysis also helps in the resolution of pyrolysis mechanism. For example, crystal substances in biochar were mainly SiO2, K2SO4, KAlSi3O8, and K2SO4 enhanced the reaction degree of biomass. While for bio-oil, the yield reached maximum (∼25 wt%) at ∼550 °C. The pH of bio-oil was acidic (2–4.3), and the main product in bio-oil was phenols, which was found the highest (84.63 %) at 700 °C. Interestingly, the interaction of cellulose and lignin promoted light hydrocarbon production. This research unveils innovative perspectives on the intrinsic mechanisms underlying microwave-assisted pyrolysis of biomass, which provides guidance for optimization of the microwave-assisted pyrolysis technology.