Temporal variability of soil phosphorus and potassium nutrients in Lingxian experimental region was studied. The results indicated that available P contents of plow layer soil samples showed a general tendency with increase of 0.33 mg.L~(-1).a~(-1) in 4 sampled times from 1992 to 1997,1999, and 2002, while soil available K contents with a decrease of 1.52 mg.L~(-1).a~(-1). Temporal variability of soil phosphorus and potassium nutrients was related to nutrient balance of phosphorus and potassium in soil-crop system. Phosphorus (P) surplus was 38.6 kg.hm~(-2).a~(-1), and phosphorus real surplus rate greatly exceeded its rational range, phosphate fertilizer was not efficiently used. Potassium (K) deficit was 95.7 kg.hm~(-2).a~(-1),and potassium real deficit rate was lower than its permissible deficit rate. If soil potassium in Lingxian experimental region was deficient for long-term, soil potassium supplying power will decrease significantly.