The shelter pipe of the tube heating furnace is positioned at the base of the convection chamber, which is subjected to the severe heat transfer conditions of high-temperature radiation and high-speed convection scouring concurrently. The heat intensity of the shelter pipe is identified as the pivotal parameter for regulating the coking of the medium within the tube to minimize the decomposition of the heat-sensitive medium and facilitate the selection of materials for the furnace tube. However, the traditional calculation method for the shock tube can only obtain the average thermal intensity of the shock section, which cannot meet the requirements of refined design. This paper employs a numerical simulation method to study the detailed heat intensity distribution of the shelter pipe and its influence on the law. The results show that the flue gas temperature and flow rate are the key factors affecting the heat intensity of the shelter pipe. The first row of the shelter pipe exhibits the highest heat intensity peak, emphasizing the need for particular attention to the design of the shelter pipe. The second and third rows of the shelter pipe show a significant reduction in peak heat intensity. The present study has developed a novel model for calculating the heat intensity distribution of the shelter pipe applicable to engineering design. This model is based on the simulation results and heat transfer theory. It can calculate the average and peak heat intensity of each row of the shelter pipe and overcome the shortcomings of traditional calculation method,. Furthermore, the error of the model calculation is less than ±5%, which can provide theoretical basis for the engineering design and precise optimization of shock tubes in the tube furnace.