The anti-floating anchor bolt is an important technique to control groundwater buoyancy in construction works. The anti-floating anchor bolt project for the underground square foundation pit in north Xingyuhuafu in Qingdao was taken as the research object. The preliminary design was carried out based on the existing anti-floating anchor design theory, and the numerical simulation test was carried out using FLAC3D. The stress and deformation of the foundation pit floor under the combined action of structural loads, underground water buoyancy and anchor bolts were analyzed. The optimization scheme for anti-floating anchor bolts was obtained through trade off of the loading conditions and construction cost.