In open sea region with severe wave attacks, a breakwater covered with wave-dissipating blocks have been widely used. However, the application of this breakwater at greater depths implies the increase of construction costs because it requires a large quantity of wave-dissipating concrete blocks. Therefore, the authors developed a new type of breakwater. This breakwaterconsists of wave absorbing caisson and sloping top caisson. In this paper, through the sliding experiment of this new type breakwater using a 1/60 model, we prove the stability and define the hydraulic characteristics of this breakwater.