利用莱州市平原区近二十年来大量水质、水位调查资料，对海水入侵和地下水位负值问题进行研究发现，二者的发生、发展具有明显的阶段性：Ⅰ（1970～1975年），地下水位大幅度下降，无负值区，季节性、零星海水入侵；Ⅱ（1975～1979年）小型园形负值小漏斗，多个孤立海水入侵小区；Ⅲ（1980—1985年），椭圆形负值漏斗，顺岸连片海水入侵；Ⅳ（1986—1989年），宽带状负值大漏斗，海水入侵区移入漏斗区近海侧，海水入侵速度最大；Ⅴ（1990～1995年），负值区整体向陆移动，海水入侵速度减缓。 Based on a large amount of water quality and water level survey data in the past 20 years in the plain area of ​​Laizhou City, the paper studies the seawater intrusion and the negative value of groundwater table. The occurrence and development of the two have obvious stages: Ⅰ (1970-1975), groundwater (1975-1979) small garden negative small funnel, a number of isolated seawater intrusion area; Ⅲ (1980-1985), the oval negative (1986-1989), large-width negative negative funnel, seawater intrusion zone moved into the funnel area near the sea side, the seawater intrusion rate was the highest; Ⅴ (1990-1995), the negative zone The overall move to land, sea water intrusion rate slowed down.