Current wind-resistant design specifications for long-span cable-supported bridges adopt single-girder， twin-girder， and triple-girder models to analyze wind-induced responses. These models typically assume that the cable anchor points align horizontally with the bridge deck’s torsional center， ignoring the additional torque induced by cable anchorage eccentricity. This study underscores the importance of incorporating cable-girder anchorage eccentricity to accurately estimate wind-induced deformation in long-span cable-stayed bridges. First， based on the deformation compatibility between anchorage components and the elastic deformation of stay cables， a simplified calculation method for cable anchorage eccentricity is established. Then， a revised analytical framework was developed to calculate nonlinear torsional deformation， fully accounting for cable-girder anchorage eccentricity. A numerical case study on the Sutong Yangtze River Highway Bridge indicates that the additional torque by cable-girder anchorage eccentricity exceeds 20% of the aerostatic torque derived from the bridge deck’s aerostatic torsional coefficient. When the anchorage eccentricity is taken into account， the mid-span torsional deformation of the main girder increased by 67.7% and 26.7% at wind attack angle of 0° and 3°， respectively， while the critical onset velocity of aerostatic instability decreases by 6.3% and 3.0%， respectively. This increased torsional deformation further alters the additional wind angle of attack effect on the main girder.