Abstract: Landfill slip will cause losses of lives and properties and serious environmental pollution. At present, the methods for stability of landfills are few. The drainage well to control the stability of the landfill at an instable landfill in China is investigated. The surface horizontal displacement, deep lateral displacement and leachate level are monitored to evaluate the method. The seepage and stability analysis software is used to analyze the effects of stability control of pumping time, pumping rate and arrangement. It is shown that after using this method the maximum slip area is reduced to 17% from the monitoring area of 68%, and the deep average slip rate is reduced to 0.95 mm/d from 2.43 mm/d. The maximum pumping rate of 10 drainage wells is 279 m³/d, and the average pumping rate is 164 m³/d. The simulation analysis shows that the longer the pumping time and the greater the pumping rate, the faster the landfill tends to be stable. Under the same flow rate, 3 rows are superior to the arrangements of 1 row and 2 rows in terms of slip control. Under the same row number of 2, the effectiveness of row spacing of 10 m is superior to that of 20 m. The proposed method has been proved to be successful in practice, and the application of drainage well may provide a successful example for control of the similar landfill slip.