Abstract: Irrigation-nitrogen regulation is one of the most important measures to increase crop yield in agricultural production. The two main local winter wheat cultivars, Jimai 22 and Shimai 15, were used in a field experiment to investigate their grain-filling characteristics and nitrogen, phosphorus and potassium accumulation dynamics under limited irrigation and nitrogen in the North China Plain. The experiment was carried out at the Wuqiao experiment station of China Agricultural University in the 2009-2010 growth seasons. There were two irrigation treatments: W₁ (spring irrigation at jointing stage) and W₂ (spring irrigation at jointing and anthesis stages); and two nitrogen fertilizer treatments: N₁ (192 kg/ha) and N₂ (270 kg/ha). The results showed that at the grain-filling stage the grain weight of superior and inferior spikelets for both cultivars presented a “S” variation tendency, whereas the grain-filling rate presented a parabola variation tendency. The grain weight and grain-filling rate of superior spikelets was significant higher than inferior spikelets in both cultivars. Under the same irrigation level, grain-filling durations of superior and inferior spikelets in the N₁ treatment were higher than N₂, whereas the grain-filling rate was contrary. Under the same N level, the grain-filling durations of superior and inferior spikelets in W₂ was higher than W₁. Under different irrigation and nitrogen regimes, grain weight, grain-filling rate and durations of superior and inferior spikelets of Jimai 22 were higher than Shimai 15. During the grain-filling period, grain nitrogen, phosphorus and potassium accumulation amounts present a “S” variation tendency in both cultivars. Under the same irrigation level, grain nitrogen, phosphorus and potassium accumulation amounts in the N₂ treatment were higher than N₁. Under the same N level, grain nitrogen, phosphorus and potassium accumulation amounts in the W₂ treatment were higher than W₁. Under different irrigation and nitrogen regimes, the grain nitrogen, phosphorus and potassium accumulation amounts of Jimai 22 were higher than Shimai 15. The results suggest that moderate irrigation and nitrogen supply enhances the grain-filling rate of superior and inferior spikelets at the late grain-filling stage, prolongs grain-filling durations, promotes balance filling of superior and inferior grains and equilibrium in the distribution of nutrient elements, improves grain weight and quality, producing in sum high yield gains and efficiency.