Abstract: Antifloating anchors can be used to solve the antifloating problem of large substructure, but there is no available code to be abided by in design and construction of antifloating anchors. The test and research on antifloating anchors is carried out based on the large substructure in coastal region. The distribution of shear stress between softrock and mortar are obtained through the test. The test shows that the shear stress distribution is not uniform and the shear stress attenuates along the length of anchors. From the orifice to holebottom, the pullout resistances of antifloating anchors are also obtained according to the destructive test, which provide the basis for the design of antifloating engineering. The practical project shows that it is very economical and reasonable that anchors are used to solve the antifloating problem of large substructure.