Aiming at the determining method for the crest elevation of low-crested sloping island breakwater,we discuss key factors affecting the design of the crest elevation of low-crested sloping island breakwater on the basis of existing research findings and the engineering practice under study.For situations where strong waves are scattered and common waves are concentrated,we propose a design concept that the crest elevation should make the secondary waves behind the breakwater and design waves of the non-protected wave direction substantially equivalent,and compare and analyze results of physical model tests in engineering cases.The results show that the proposed design concept is rational and feasible,which has reference significance for the design of similar future projects.