The invention discloses a positioning buckle system on a screen frame for recovering topsoil of degraded grassland in a mountain desert steppe. The screen frame comprises a fixing pile and a filter screen assembly which can be separated from each other. A plurality of foldable brackets are arranged on the fixing pile and used for fixing the fixing pile on the ground rapidly and conveniently without affecting storage and transportation of the fixing pile. The filter screen assembly comprises a filter screen main body and two connecting columns arranged at the two ends of the filter screen mainbody correspondingly. The filter screen main body can be wound on the connecting columns, so that the distance between the two connecting columns is adjustable. Mounting holes for accommodating the connecting columns are formed in the fixing pile in the vertical direction. The positioning buckle system comprises hole plugs. The hole plugs are used for being buckled to openings of the mounting holes in which the connecting columns are arranged, so that the connecting columns and the mounting holes are fixedly connected.