Based on the total stress method, a three-dimensional FEM numerical model of suction caissons in saturated soft clay is presented by the finite element analysis software ABAQUS. The numerical model is verified by the laboratory test results. In the numerical analysis, the load bearing characteristics, failure mechanism and the envelope diagram on the optimal mooring point are investigated. By fitting analysis of the numerical results, a simplified method for the estimation of the uplift capacity for suction caissons is described. The expressions developed in this paper take into account the influence of the aspect ratio of the caisson, angle of inclination of the loading and the undrained shear strength of the soil.