Proposed that ground is a continuous environment, stress status of a point in ground in the flat stress problem is defined as stress components Dx, Dz, Txz satisfying static balancing condition. This system of equations has various roots, the problem is indefinite. This problem can become definite by adding more condition of the max shear stress at minimum (Tmax - min) at each point in ground. Based on the obove mentioned stress theory, this paper presents the