Abstract: The inclination of high-rise building structures can increase the structural P-Δ effect, thereby increasing the deformation and internal forces of the structure, which has many adverse impacts on structural safety, serviceability, and economic value. Chinese building codes impose strict limits on building inclination rates. Specifically, the Code for Design of Building Foundation (GB 50007−2011) stipulates that for multi-story and high-rise buildings exceeding 100 meters in height, the overall inclination rate shall not exceed 0.2%. Focusing on the coupling characteristics between inclination and the P-Δ effect, this study employs the cantilever Euler beam theory to investigate the deformation and internal forces of high-rise structures. Based on a vertical concentrated load model and incorporating the corrections derived from a uniformly distributed load model, a modified calculation formula is proposed to quantify the amplification of deformation and internal forces when considering the coupling between inclination and P-Δ effect. The calculation results indicate that the inclination rate, stiffness-to-weight ratio, and shear-to-weight ratio are three key parameters influencing structural deformation and internal forces. The amplification of internal forces is found to be smaller than that of deformation. From the perspective of controlling deformation amplification, this study provides inclination rate limits for deformation amplifications within 5% and 10%, based on the proposed modified calculation formula. The results indicate that for common high-rise structures with a shear-to-weight ratio below 3%, the maximum inclination rate should not exceed 0.10% when the deformation amplification is controlled within 5%, and should not exceed 0.23% when the deformation amplification is controlled within 10%.