Silicon compounds as reinforcement agents in wood modification have an increase improvement in durability, dimension-stability and photostability, fire resistance, and certain mechanical properties such as surface hardness, tensile strength. Two kinds of silicon compounds reinforced poplar wood composites were fabrication by sol-gel and dipping silicasol respectively. The thermal properties of these materials were conducted by TG, and thermokinetic models and equations in process of pyrolysis were established by Doyle calculation. Results show that wood based composites with improved fire resistance were well fabricated, and temperature scopes of thermal pyrolysis of these composites were decreased from 420 °Cto 380°C compared with poplar wood, but activation energies increased from 322.8 kJ•mol-1 to 421.1 kJ•mol-1. Wood substrate was protected for introduction of silinon compounds in certain degree.