The Jiaozhou Bay, covering an area of 390 km2 between 3538′ and 3618′ N and 12004′ and 12023′ E, surrounded by the Qingdao city. As a semi-enclosed, fan-shaped bay, the narrowest place at the channel connecting with the Yellow Sea, from the Tuan Island to the Xuejia Island, is only 3000 m wide. Its average depth is 6-7 m, with most part of the bayshallower than 5 m, and the tidal zone adds up to 125 km2. The tide of Jiaozhou Bay is regular semidiurnal type. The speed of the flood is greater than that of the ebb, and the duration of the flood is shorter than that of the ebb. There are many peninsulas and islands in the bay, so the circulation inside is complicated. After the residual current analysis, six circulation systems were observed in Jiaozhou Bay. Marine biodiversity and productivity is high in the bay. With the development of Qingao City, the population is increasing quickly around Jiaozhou Bay. Farms, factories, highways, ports, tourism etc. can all affect the environments of the bay. Most of the land-sourced input are from several rivers, such as the Dagu, Haibo, Licun and Nan Jiaolai rivers.