Casing damage in the horizontal screen section of thermal recovery wells has long been a critical challenge hindering the efficient and sustainable development of heavy oil reservoirs. Clarifying the main controlling factors of casing damage in these sections and establishing parameter limits to prevent casing damage are crucial for guiding the safe development of thermal recovery wells in heavy oil reservoirs. Based on thermo-mechanical coupling theory，a finite element model incorporating parameters such as steam injection temperature，dryness，wall thickness of the horizontal screen，and the screen phase angle was developed. Based on the control variable method，numerical simulations were conducted to analyze the influence of steam injection parameters（temperature and dryness）and structural parameters of the horizontal screen（wall thickness，phase angle，pore diameter，and pore density）on casing damage under the combined effects of fully compensated axial thermal expansion，overlying rock pressure of horizontal screen，and formation expansion-induced stresses on the horizontal screen. The results demonstrate that the primary controlling factors for casing damage in the horizontal screen section are the wall thickness of the screen，steam injection temperature and dryness，and phase angle of the screen. Increasing the wall thickness of the screen significantly reduces stress and mitigates casing damage risks. Elevating steam injection temperature and dryness in the horizontal screen section of thermal recovery wells enhances heavy oil recovery，and it substantially increases stress on the horizontal screen section，thereby amplifying casing damage risks. The screen exhibits optimal collapse resistance at a 30° phase angle，with stresses rising by 13.2%，25.6%，and 2.8% at 60°，90°，and 150° phase angles，respectively. The safety ranking of phase angles follows 30°，150°，60°，90°. Pore density and diameter show relatively minor impacts on casing damage. Based on these findings，four technical limit charts for casing damage prevention are established. These charts enable rapid determination of casing damage prevention strategies for the horizontal screen sections of thermal recovery wells.