Abstract: Maximum saturated depth is an important parameter in designing of landfill leachate dramage systems. Dased on the groundwater flow continuity principles, Dupuit assumptions and extend Dupuit assumptions, phreatic surface governing equations were established over the landfill with slope liner in continuous-slope configuration drainage system, respectively. These equations were solved by numerical calculation. Though computation and analysis of change parameters, the results indicate that Dupuit assumptions can be used to calculate the maximum saturation depth as the slope of landfill liner is less than 10%. When geonet is employed in continuous-slope configuration drainage system, transmissivity of geonet and slope of landfill liner are important influence factors for maximum saturation depth, hydraulic conductivity of protect layer and impingement rates for efficiency of drainage system can't be ignored. At the same time, compared the efficiency of continuous-slope with saw-tooth configuration's in level landfill liner, the results show the former is better than the latter.