To understand the factors of increasing yield in the machine transplanting seedling nursing techniques of early rice in South Hunan province, we conducted field experiments in Hengyang county, Hunan province in 2017-2018. Three spraying periods of paclobutrazol, spraying on 1 leaf 1 heart period (A1), spraying on 2 leaf 1 heart period (A2), spraying on 1 leaf 1 heart period and 2 leaf 1 heart period (A3), and four seeding rates (dry seed), 75 g/plate (B1), 90 g/plate (B2), 105 g/plate (B3) and 120 g/plate (B4) were used in the experiment to explore the effect on yield of a early rice, Zhongjiazao 17. The results showed that seedling rate, total roots number per plant, average root length, stem width and dry matter weight per 100 plant of early rice were increased by the increment of seeding rate. There existed significant effect of seeding rate and spraying period of paclobutrazol on antioxidase activities of seedlings, and those of B3 treatments were higher. Tillering speed of treatments with lower seeding rate was faster, and the effective panicles were increased with the increment of seeding rate. Seeding rate had significant effects of leaf area index and dry matter accumulation of upland parts, and those of B3 treatments were higher. Seeding rate and spraying period of paclobutrazol had significant effects on yield and its components. Within seeding rate treatments, B3 treatment had the higher effective panicles, grains per panicle, seed setting rate and yield, and within treatments of spraying period of paclobutrazol, A2 treatment had the higher yield. There existed significant interaction on yield between seeding rate and spraying period of paclobutrazol, yield of A2B3 and A1B3 was the highest in 2017 and 2018, respectively, and the total yield of two years of A1B3 was the highest. These results showed that the optimal conditions were 105 g/plate for seeding rate, 1 leaf 1 heart period for spraying method. The yield enhancement was due to heighten grains per panicle and seed setting rate, which were probably resulted by improved inverse resistance of seedlings, promoted dry matter accumulation.