Abstract: Aiming at the exist problems of the research on laws of void water seepage in low osmosis stratum,with means of microseepage-consolidation combined test,triaxial percolated consolidation test,hydrargyrum intrusion test and other tests,this paper details a systemic research on seepage laws of void water in low osmosis stratum- cohesive soil,and discuss void water seep law,utmost hydraulic graddient,the applied scope of Darcy-law,and its applications in practice.