Abstract: In order to explore the effect of nitrogen fertilizer on the growth of young seedlings of Cyclobalanopsis gracilis, the response to nitrogen application of growth, biomass, and physiological indicators of C. gracilis seedlings was investigated with the methods of average nitrogen application and index nitrogen application. Principal component analysis and membership functions were used to screen for the optimal fertilization mode and level. The results showed that under the average fertilization mode, the maximum plant height and biomass of C. gracilis seedlings were achieved at a total fertilization amount of 1 600 mg·plant^-1, and the maximum ground diameter of C. gracilis seedlings was achieved at a total fertilization application of 1 200 mg·plant^-1. Under the index fertilization mode,when the total nitrogen application amount was 400 mg·plant^-1, the height, diameter, and biomass of the seedlings of C. gracilis were the highest. Through principal component and membership function analyses, a comprehensive evaluation was conducted on 13 treatments. The most suitable nitrogen application treatment for the growth of C. gracilis young seedlings was ultimately selected as a total fertilization amount of 1 600 mg·plant^-1under the average nitrogen application mode. Compared with exponential nitrogen application, the average nitrogen application mode had a simpler fertilization procedure, which was easier for operators to master and more suitable for the growth of young seedlings of C. gracilis. It was recommended to promote the application of a total fertilization amount of1 600 mg·plant^-1as a fertilization measure for the cultivation of high-quality and strong seedlings of C. gracilis in production.