Abstract: Taking Zhengdan958,Xianyu335,Jundan 20 as test materials,the experiment studied the N,P2O5,K2O content,absorption,accumulation amounts and equilibrium absorption of the summer-sown corn in the medium-low-yidld areas of Heilongjiang plain.The results showed that nitrogen and phosphorus contents were decreased with the growth stage while the potassium content of maze showed a unimodal curve during,and the maximum was at the node protracted stage.But the N, P2O5 and K2O consumption was increased with growth stage. The rate of nutrient uptake was not in the same way all the time, but changed from one time to another. Usually, the rate was increased fast at early stages, and gradually decreased after reaching their peak.For N, P2O5 and K2O, the uptake rate for N and K2O was higher, and their increase and decrease were both fast while P2O5 was in reverse case. The time for the maximum absorptive rate appeared in the same time-the anthesis, and the bigger is K2O, followed by N, and then by P2O5 . All of their accumulation percentage of N, P2O5 and K2O was achieved 50% in the anthesis. It indicates that to assure enough nutrient is the basis of high yield.