Dongbi Island is located in the east of Dongying Village, Longtian Town. Qi Jiguang, an anti-Japanese hero in Ming Dynasty, regarded it as a barrier to Haidong, so he called it "East Wall". Dongbi Island looks at Mazu Island in the north and Haitan Island in the east, and is located in the sandy coastline area of subtropical seashore. The island is 3.88km long from north to south, with a maximum width of 1 km, an area of 2.64km2 and a coastline of12.38km.. There is a magical "fountain of youth" on the island, known as the "dead sea"; There is the "Nine Ambassadors Belief" which embodies the ancient "snake" totem worship of Fujian people; A sandbar on the sea with the beautiful legend of "the dragon saves people"; There is a "Haihe River" which is called the gateway to the immortal country. It is particularly worth mentioning that there is a mysterious cave on Jiushi Mountain on Dongbi Island, which is said to be more than ten kilometers long and leads to Dongying Village and Jiaru Village in Sanshan Town. Legend has it that there was once a man who was trapped in a hole for three years and went crazy after coming out. Bold local villagers once wanted to explore the cave, but when they arrived at the cave, all the lights went out and the spread was very mysterious. The villagers think that this cave is the residence of the Nine Ambassadors. In order to respect the nine ambassadors and protect them from outside interference, the cave was sealed by the villagers.