Abstract: This paper discussed macro and micro scopically the permeability and release deformation of deep clayey soil in Haikou,and brought out the conclusion that the complex settlement of constringent layer (including shallow soft soil and deep hardy soil) would occur because the deep artesian water had been exploited, so we considered that the deformation of hardy soil could not be ignored and the permitted water level should be decided by allowable bearing capacity of soil.Then the suggested method of settlement calculation is simple.