Abstract: As an important depositional morphological feature along a coast, the beach and its stability are of great significance for development, utilization and nourishment. In this paper, the stability of the Mingzhu Square Beach, an manmade beach around the Chang Island and the Moye Island Beach of Rongcheng are studied based the topographic profiles and grain-size data from beach surface. The parabolic bay model (MEPBAY) is adopted to analyze and predict the stability of the two beaches. Results show that the Mingzhu Square Beach remains in an unstable stage with severe erosion of foreshore, and the Moye Island Beach is in a slightly unstable stage with rather weak erosion. On the basis, we briefly discussed in this paper the reasons that cause erosion from island beach geographical features, hydrodynamic environments, sediment sources and human activities.