Coupling effect of water (readily available water) and phosphorus on N, P, K uptake by winter wheat seedlings was studied. The results showed that availability of water had a notable effect on N, P, K uptake. The peaks of N and P uptake were always observed in treatments with a high level of readily available water regardless of P levels. When the level of readily available water went down, the uptake of N and P was also down. The coupling of moderate P rate with a high level of water was most contributive to P and N uptake. When the water level was low, increasing the input of phosphorus can improve absorption of P, but had no effect on absorption of N. The effect of readily available water on K uptake by the seedlings was not so obvious as that on P uptake. The experiment also showed in treatments low in P input seedling P uptake was significantly lower, and increasing P input can increase plant P uptake regardless of water levels. Soil P stress also had same effect on wheat K uptake. The coupling effect on K uptake varied sharply with the variety of the crop.