The ratoon crop of ratoon rice, after the mechanical harvesting of the main crop, often faces issues such as low yield and high broken rice rates. Foliar nitrogen application is a simplified fertilization technique that effectively supplements the crop's nitrogen requirements, enhancing both quality and yield. This study investigated the effects of different foliar nitrogen application rates on the growth, yield, and quality of ratoon crop rice, aiming to provide a theoretical basis for achieving high yields through mechanical harvesting and simplified fertilization in ratoon rice production. A field split-plot design with two factors was employed following the main crop rice harvest in both high-fertility (HF) and low-fertility (LF) fields. The main plot factor was rolling status (rolled and non-rolled), and the sub-plot factor was foliar nitrogen application rate, with six nitrogen gradients: 0 (N0), 1.0 (N1), 3.0 (N3), 5.0 (N5), 7.0 (N7), and 9.0 kg/hm²(N9). The results showed that, in HF, foliar nitrogen application treatments increased yields by 13.6%-37.4% in rolled areas and 35.1%-39.7% in non-rolled areas compared to N0, with the highest yields in N9 and the lowest in N1. In LF, yields increased by 15.6%-38.8%(rolled areas) and 22.3%-38.6%(non-rolled areas), respectively. Specifically, in the rolled area, the highest yield was observed in N9 and the lowest in N1, while in the non-rolled area, the highest yield was in N3 and the lowest in N1. Compared to the N0 treatment, foliar nitrogen application improved both milling and appearance quality of the ratoon crop rice to varying degrees. In rolled areas of HF, foliar nitrogen treatments significantly increased milled rice rate and head milled rice rate by 31.6%-37.5% and 65.3%-71.5%, respectively, and significantly reduced chalkiness by 20.4%-35.3%. In non-rolled area of HF, milled rice rate and head milled rice rate increased significantly by 27.2%-32.2% and 46.7%-57.0%, respectively, with chalky grain rate significantly decreased by 22.8%-38.5%. In rolled area of LF, milled rice rate and head milled rice rate increased significantly by 31.8%-37.9% and 53.4%-70.3%, respectively, with chalky grain rate significantly decreased by 20.5%-35.5%. In non-rolled area of LF, milled rice rate and head milled rice rate increased significantly by 34.9%-40.8% and 49.4%-60.2%, respectively, with chalky grain rate significantly decreased by 22.8%-38.5%. Based on the results, the optimal foliar nitrogen application rates for the ratoon crop rice under mechanical harvesting conditions of the main crop were recommended as 4.1 kg/hm² for rolled areas and 3.0 kg/hm² for non-rolled areas.