Based on data from the investigation in Jiaozhou Bay waters in 1982,the distribution,transfer and seasonal variation of As in Jiaozhou Bay were analyzed. Research results showed that in Jiaozhou Bay,As content was 0. 22-2. 80 μg /L at surface layer in one year and 0. 84-4. 48 μg /L at bottom layer. In one year,there was no As pollution in the whole waters of Jiaozhou Bay,and only low-content As was input into Jiaozhou Bay. By the horizontal distribution in the waters,it was able to determine if the mater was transported from the land into the waters and what the way of the transportation was. In April and October,there was no As source in the bay; the As content came from the river transportation in June and from the surface runoff transportation in July. In the land transfer process,the As content change in waters of Jiaozhou Bay was determined by the rainy season. There was no pollution of As in the soils and waters around the bay,so the As content was very low in the rivers around the bay.In the waters transfer process,in July and October,if there was the As source in the waters of Jiaozhou Bay or not,the bottom area with the highcontent As was formed in the bay center.