Pyrolysis behavior of bio-based resins is of increasing interest due to their great potential in environmentally friendly and high-temperature application. Herein, the high-temperature stability, pyrolysis kinetics and mechanism of rosin glyceride (RGE), hydrogenated rosin glyceride (HRGE), C9 petro-based resin (C9PR) and hydrogenated C9 petro-based resin (HC9PR) under non-oxidizing atmosphere were investigated by TG-FTIR/MS techniques. Based on the non-isothermal TG data, activation energy was calculated by Friedman and Starink methods, and the reaction-order model of f(α)=(1-α)n was found to be the most probable pyrolysis mechanism for different resins, which was also supported by the TG-FTIR/MS results showing only a dominating pyrolysis peak. Furthermore, thanks to the unique tricyclic phenanthrene structures, bio-based resins exhibit better high-temperature stability than petro-based resins, with an initial skeleton cracking temperature of 623 K and 573 K, respectively. High-temperature stability of resins would mildly decrease after hydromodification due to weak bonds cracking. Possible pyrolysis pathways were proposed.