Saltwater intrusion a risen in the lower reaches of the Weihe river has drastically devastated the regional economy,society a nd ecological environment.Based on deeply analyzing the mechanism of saltwater intrusion and the groundwater regime regularity.The scientific monitoring method of saltwater intrusion regime and the lay out of monitoring network are probed into.Three kinds of monitoring network are constructed:(1) the monitoring network of the water resources supplies and demands;(2) the monitoring network of groundwater table and qua-lity regime;(3) the monitoring network of geophysical methods.