Three waters of different trophic states in the Huaibei and Huainan coal mining subsidence areas,including sites HBNH, PXGQ and PXXQ,were chosen to address their nutrient content,ratio of nitrogen to phosphorus (N: P),and nutrient limitation.Averaged annual concentrations of total phosphorus (TP) in the three sites are 0.056,0.064 and 0.092 mg/L,while the total nitrogen (TN) concentrations are 1.00,0.94 and 2.67 mg/L,respectively.The three studied waters present two trophic levels of "meso-trophic to light eutrophication" and "meso-eutrophciation" with deficiency of phosphorus.Nutrient enrichment bioassays were performed by four groups' experiments.Three treatments were cultured with additions of nitrogen (+N),phosphorus (+P),and nitrogen plus phosphorus (+N+P),with raw water without additions as control.HBNH and PXXQ show features of P limitation,and the other one,PXGQ presents N limitation due to its lower available inorganic nitrogen.Although very low phosphate concentrations,the three sites still have rather high primary production,with their chlorophyll-a concentrations of 13.07 (HBNH),26.95(PXGQ) and 46.25 mg/m³ (PXXQ),which are in accordance with their nutrient states.The results of this research give implication of the importance of P control to these waters in the Huainan and Huaibei coal mining subsidence areas.