The entrance to the Yangtze River is the key part of linking tributaries to the Yangtze River, and the bed stability is important for the smooth transport of waterway. By taking the entrance of Qinhuai river and the entrance of Chengnan river of Nanjing reach as the research cases, we analyze the features of the beach evolution.Based on the existing data on dredging, we study the effect of beach evolution on the entrance waterway to the Yangtze River. The research results show that the beach evolution not only forms the local conditions of the entrance waterway, but also affects the water and sediment condition, thus it has great influence on the current, sediment motion and waterway of the entrance to the Yangtze River.