A numerical simulation model based on finite element analysis was established in this article to determine the temperature distribution in wood during an insecticidal heating treatment. The calculated temperature was compared with that measured from a typical operation and shows the feasibility of applying finite element analysis to predict the thermal response of wood. On the basis of the results, further experiments were conducted to analyze the effects on the shape of wood sections, the temperature elevation rate and heat preservation value as a result of the thermal response of wood. The calculated results provide a theoretical reference for designing a monitoring system and operating process for insecticidal treatment of wood.