Deformation characteristics of soil samples in Tianjin city under unloading are studied through a large number of indoor consolidation-rebound tests.The critical unloading ratio R=0.2 where rebound happened and the unloading ratio R=0.9 where strong rebound happened are confirmed after analyzing the relationships of rebound ratio-unloading ratio and rebound modulus-unloading ratio.These two ratios can be used to estimate the depth of unloading influence area and strong rebound area.Therefore,the study in this paper can provide some guidance to design and construction in such unloading projects as foundation pit.