Abstract: Sea (salt ) water intrusion is one of main geologic hazards in coastal Qingdao. It mostly occurs around main estuaries into the Jiaozhou Bay. Sea water and ancient seawater or high mineralized underground salt water intrude to the land along the aquifer due to over exploitation of groundwater around the intrusion zones. As the result, groundwater resources are contaminated. Based on the study of the formation mechanism of the disaster, prevention measures are proposed in this paper.