Through the field investigation of 30 sections and profile characteristics of the sedimentat of the Xiamen Bay Beach, as well as numerical simulations of the tidal current field and the wave field, the beach type of Xiamen Bay is divided from the perspective of dynamics. It was figured out that there is “sandy-muddy hybrid beach” in addition to the sandy beach and muddy beach, and in the environment of the muddy coast, strong coastal waves and supply of the coarse-particle sedimentmay produce sandy-muddy hybrid beach. The concept of “sand-silt demarcation point” is proposed and applied in artificial beach problems. It can be found that the elevation of sand-silt demarcation point mainly depends on the local wave condition.