The economy in Taihu Basin of Jiangsu Province is developing very quickly, which has led to large increase of water demand for urban and industry use. Overexploitation of underground water has given rise to serious land subsidence. At present, the area of land subsidence in Suzhou, Wuxi and Changzhou has reached 5000 km². Land subsidence has great influence on the security of water supply and has increased the expanse of flood mitigation. Closing the deep wells, adjusting industrial structure, quickening the development of regional water supply and strengthening comprehensive water management are important measures to control land subsidence.