Abstract: The field monitoring results from a large landfill in Northwest China are introduced. The monitoring items include leachate level, surface horizontal displacement and deep lateral displacement at the landfill. The monitoring results show that there were 3 large slips in the landfill from April to August in 2014, caused by garbage load, dynamic load and heavy rainfall. The maximum sliding area is 30029 m² and the sliding depth is 17 m. By monitoring and back-analyzing the overall process of the slope sliding of a landfill in the Northwest region of China, the slip principles of the slope are got, that is, the factors include garbage load, dynamic load, leachate level and heavy rainfall. The antislip effects of the measures of drawdown of leachate level by pumping, stratified compaction and geotextile reinforcement are analyzed. It is shown that the requirements of stability can be satisfied when using the measures of drawdown of leachate level by pumping, compaction and geotextile reinforcement.