Abstract: By the model tests to study on the influence of unilateral surcharge in subsoil bearing capacity characteristics under non surcharge case and unilateral surcharge case. The subsoil bearing capacity,the stress distribution and the failure mechanism are analyzed. The soil is dense medium sand. The results show that the bearing capacity is obviously improved and the settlement of subsoil is obviously restrained under the unilateral surcharge case than the case without surcharge. The vertical stress distribution of subsoil is no longer symmetrical and stress in the surcharge side has increased. The failure mechanism of the subsoil is asymmetric. Under the action of unilateral surcharge, the horizontal failure zone length is shorter and the subsoil uplifts less than the case without surcharge.