Tangdao Bay is surrounded by two headlands, and at the entrance of the bay is the famous Tangdao Island. Tangdao Island is very small, covering an area of only 0.07 square kilometers. However, it is quite renowned. According to legend, during the Tang Dynasty, Emperor Taizong of the Tang Dynasty personally led the navy on an eastward expedition and once stationed on this island, so it was named Tangdao Island. Many years ago, many ancient weapons such as knives, swords and arrowheads were indeed unearthed on the island.

However, the existing historical materials still cannot prove that Emperor Taizong of the Tang Dynasty really stationed the navy here. Nevertheless, during the Southern Song Dynasty, a famous naval battle in Chinese history did take place here.