Abstract: Based on the relevant theories of heat transfer and elastoplastic mechanics, in combination with the actual sealing conditions of cement sheath, this study establishes two sets of mathematical models:a temperature field model of wellbore for any type of gas well, a model of the temperature field and thermal stress field of the casing-cement sheath-surrounding rock assemblage, sets up analytical solution algorithms and engineering analysis software, and studies the influence factors of temperature stress field. The study shows that the yield has a great influence on the temperature field of wellbore. The temperature of the shallow cement sheath of high-pressure and high-yield gas wells rises obviously, and the changes in the temperature field and temperature stress field should be analyzed and predicted in advance to determine whether to add sand to improve heat-resisting property. Cement sheath with good toughness, low elastic modulus, high strength (especially tensile strength), and high longitudinal bonding strength can maintain good sealing property under the condition of high temperature rise. Two or more layers of cement sheath has a higher safety factor than that of single-layer cement sheath. The research results help to analyze and predict the effect of temperature on the effective sealing of cement sheath, and optimize the design of cement slurry system.