To test the appropriate proportion of slow-release nitrogen (N) to the total N application in the one-time application strategy for single-cropping rice, to provide theoretical guidance for efficient fertilization of single-cropping late rice, a field experiment was carried out in Heping Town, Changxing County, Zhejiang Province from 2019 to 2020. The experiment consisted of six treatments: (1) No N fertilizer (N0); (2) Conventional fertilization (U1, base fertilizer∶tillering fertilizer∶panicle fertilizer=4∶3∶3); (3) Reduction conventional N rate by 12.5% (U2, the proportion was the same as U1); (4) 57% slow-release N with one-time application (SRU1); (5) 45% slow-release N with one-time application (SRU2); (6) 34% slow-release N with one-time application (SRU3). The N application rate was 240 kg/hm² for U1, and 210 kg/hm² for U2 and SRU. The rice yield, nutrient uptake, nutrient utilization efficiency, ammonium N content in-field water, and ammonia volatilization were measured. The results showed that the yield of single cropping rice in N0 was 73.55% of that in U. Compared with U, one-time application of slow-release N fertilizer could maintain rice yield. The yield of single cropping rice tended to increase with the increase of the proportion of slow-release N application. There was no significant difference in aboveground N content and N uptake between SRU and U. Compared with U, the N use efficiency of SRU2 in 2019 and SRU1 in 2020 increased by 10.49% and 8.84% respectively, reaching the significant difference level, but there was no significant difference between other treatments and U1 and U2. Compared with U, SRU significantly reduced the content of ammonium N and cumulative ammonia volatilization in-field water, but there was no significant difference among slow-release fertilizers. According to the results of related yield and N loss, one-time application of 34% slow-release N application ratio could meet the nutrients requirements of single cropping rice, ensure stable rice yield and reduce N runoff and volatilization loss at the same time.