Water retention behavior is an important parameter for use in analyzing and predicting the shearing behavior of unsaturated soils. This study investigated the relation between water-retention changing properties and some cases of void ratio using hydraulic hysteresis obtained from each unsaturated undrained and drained triaxial shearing process. The pore size distribution dependence on the void ratio is determined from the capillary tube model. The pore tube radius tends to contract as the void ratio decreases. To predict undrained and drained unsaturated shearing behaviors, the pore size distribution dependence on the void ratio is considered. Then Bishop's effective stress equation, with its suction effect term calculated from the pore size distribution model, and a modified Cam-Clay model are used respectively to ascertain the effective stress and deformation behavior. The predictions show good agreement with experimentally obtained results.