For the design of breakwater and revetment engineering，the 3-D random wave test has been widely applied to the research on the breakwater， because problems concerning the wave diffraction，overtopping，three dimensional stability，wave permeability and their mutual influences can be given a better explanation compared with the traditional 2-D random wave test.Under the action of waves with different wave directions and return periods，the 3-D stability and overtopping test for the full-size breakwater which includes the head，trunk and root is carried on，in which the armor block (12 t，18 t and 24 t double-link block) can remain stable，and the largest wave overtopping rate is about 10 L(m?s) of 50 years’ recurrence period.The conclusion on stability is the same of that by the 2-D wave flume，but there as an obvious difference for the overtopping.For the design high water level，the overtopping is about 10%～30% of 2-D model test than 3-D，which is close to the research law of PARI，Japanese.But for the extreme high water level，the gap becomes larger，and even reaches about 50%～60%.Since the 2-D section experiment adopts the positive wave，and it can’t simulate the phenomenon of actual oblique waves，wave energy transport along the breakwater and dissipation，etc.，the wave overtopping will be larger than the real value，but the result from the 3-D stability test is closer to the real situation.