With the increasing depth of building basement,rising groundwater level,and the influence of extreme weather conditions,higher requirements have been put forward for the performance of anti-floating anchors,and the limitations of traditional anti-floating anchors have become increasingly apparent.In order to address the anti-floating problem of the building with differences in structural self-weight and basement depth,we conducted detailed zoning anti-floating in different areas with high strength anchors using prestressing screw-thread steel bars instead of ordinary steel bars.The pullout capacity of a single high strength anchor can reach at 560 kN and the maximum displacement of the anchor head under a maximum test load of 840 kN is only 5.25~9.97 mm,with an average value of 7.91 mm.After unloading,the rebound rate is 18.09%~46.26%,and no damage occurred,demonstrating excellent performance.The underreamed high strength anti-floating anchor has three types of stress-strain patterns,of which(compression)-prestressing compensation-enlarged head end compression is the ideal stress-strain pattern for anti-floating anchors.It can still maintain normal convergence under a load of 1120 kN.When the pullout capacity is 560 kN,it is only in the prestressing compensation stage,which still has a great bearing potential.