In deep-water, high-temperature, and high-pressure gas wells, the phenomenon of annular pressure is widely observed. Deepwater wells typically utilize subsea wellheads, which makes it impractical to depressurize annuli B and C. As a result, this poses safety hazards related to the potential failure of tubing strings under high annular pressures, high temperature and corrosion. Addressing the safety concerns related to tubing strings under high annular pressure in deep-water, high-temperature, and high-pressure gas wells, this paper presents a predictive model for localized annular pressure. The model takes into account the dynamic coupling of annular temperature, annular volume, fluid volume, and annular pressure changes resulting from thermal expansion and ballooning effects. It also considers the combined effects of annular pressure, high temperatures, and corrosion. A tubing string safety in deep water high temperature and high pressure gas well assessment method has been developed and applied to consider the influence of annular pressure, and the model's validation has been conducted. The results indicate that when considering the influence of annular pressure, the decrease in annular pressure over time is significantly smaller than the decrease in reservoir pressure. Simultaneously, the safety factor against external collapse of the tubulars decreases further as the service time increases. Furthermore, the pressure differential between the internal and external fluids in the tubulars gradually increases with well depth, making the lowermost sections of the tubulars more prone to failure. Under the combined effects of high temperature and corrosion within the wellbore, the safety factors for tubulars against internal pressure, external collapse, and tensile loads all experience varying degrees of reduction. Particularly, the lowermost tubing strings are susceptible to a harsh, high-temperature, and corrosive environment, as well as elevated annular pressure, which increases the risk of failure. In both the design and practical production processes, significant attention should be given to addressing the safety risks associated with the lowermost tubing strings