Abstract: According to structural model test of earth and rockfill cofferdam under the action of gravity and water loading, studies of their deformation characteristics are conducted. Under the action of gravity, water loading, water overloading and constant loading over a long period of rime, the vertical and the horizontal displacement distributions are obtained. Results of tests show that the horizontal displacement is less than vertical displacement under the action of all normal loading, and the ratio of horizontal to vertical displacement is 3 :10 approximately.Simulative principle, similarity constants, model materials, measuring techniques ate .of atructural modal test of earth and rockfill cofferdam are also analysed am! discussed in this paper.