Dense planting could be a feasible method for reducing nitrogen (N) application rates without compro-mising rice grain yield in northeast and central China. It is still unclear whether reduced N application with dense planting (RNDP) can achieve higher rice yield and N use efficiency (NUE) in Jiangsu, east China. Three japonica inbred rice (JI) and three indica hybrid rice (IH) cultivars were grown in a field experiment. Their grain yield, NUE, and related traits were compared under two cultivation treatments:conventional high-yielding practice (CHYP) and RNDP. JI showed similar yields under the two treatments, while IH showed lower yield under RNDP than under CHYP, and the partial factor productivity of N and N use efficiency for grain yield increased (P < 0.05) in both JI and IH under RNDP. Compared with CHYP, RNDP reduced spikelets per panicle but increased panicles per m2 and filled-kernel percentage of JI and IH, and JI's kernel weight was increased (P<0.05) under RNDP. Shoot biomass weight and nonstruc-tural carbohydrate (NSC) content in the stem at heading and maturity of JI and IH were reduced under RNDP, while harvest index and NSC remobilization reserve were increased (P<0.05) under RNDP, espe-cially for JI. Our results suggest that RNDP could achieve a higher rice grain yield and NUE, particularly for JI, a dominant rice cultivar type in Jiangsu. For JI, the increased panicles per m2, sink-filling efficiency, har-vest index, and NSC remobilization after heading under RNDP contributed to a grain yield similar to that under CHYP.