Abstract: In order to take into account the influence of rotational deformation on the lateral stiffness of masonry walls, the elastic stiffness calculation model is modified by introducing the aspect ratio, and a modified lateral stiffness calculation model of masonry wall is proposed accounting for the influence of rotational deformation. According to the pseudo-static test results of masonry walls, the adjustment coefficient of rotational deformation stiffness is obtained preliminarily by data fitting method, and the modified stiffness model is improved. The example analysis shows that the improved model generates a smaller stiffness of the wall compared with the traditional elastic stiffness method. The larger the aspect ratio, the larger the difference is, and the less the seismic action shared by the rotational stiffness method. The stiffness of the wall with spandrel wall decreases less and the seismic effect is increased