In this paper, experiments of both the model turbine(1 k W) and the full scale(10 k W) turbine are carried out in a towing tank and a basin, respectively, and the test of the full scale turbine on the sea is conducted. By comparison between the model turbine(D= 0.7 m) and the full scale turbine(D= 2.0 m), it is shown that the maximum power coefficient increases with the increase of the diameter of the turbine. The test results on the sea are used to study the hydrodynamic performances of the horizontal axis turbine, and provide a basis for the design. Experimental results can validate the accuracy of the numerical simulation results.