Abstract: To ensure food security, there has been an extravagant use of nitrogen (N) fertilizer in paddy fields. Both the increase in N fertilizer efficiency and reduce in N loss in paddy soils are important in agricultural management and environmental protection. Here, we investigated the effects of side bar fertilization on paddy yields, N use efficiency and N loss in paddy soils and to provide reference for improvement of rice N utilization. Six fertilization treatments were used in the study-control (T1), common fertilizers with conventional fertilization method (T2, N 280 kg·hm^-2, P₂O₅ 165 kg·hm^-2, K₂O 120 kg·hm^-2), slow-release fertilizer with conventional fertilization method (T3, N 230 kg·hm^-2, P₂O₅ 165 kg·hm^-2, K₂O 120 kg·hm^-2), high slow-release fertilizer plus side bar application (T4, 230 kg·hm^-2, P₂O₅ 138 kg·hm^-2, K₂O 120 kg·hm^-2), medium slow-release fertilizer plus side bar application (T5, N 180 kg·hm^-2, P₂O₅ 123 kg·hm^-2, K₂O 120 kg·hm^-2) and low slow-release fertilizer plus side bar application (T6, N 140 kg·hm^-2, P₂O₅ 123 kg·hm^-2, K₂O 120 kg·hm^-2). The study was done in one cropping calendar at the Agricultural Environmental Sciences Observation Station in Yueyang City, Hunan Province, China. The results showed that combined application of slow release N fertilizer and side bar application method increased rice yield, promoted N utilization rate and reduced N loss in paddy fields. Particularly for T4, yields of both early and late rice increased respectively by 13.17% and 4.72%, and decreased rice planting density and applied N amount, compared with T2. The yields of both early and late rice under T4 treatment were 7.27% and 1.74% higher, respectively, than that of T3 treatment. Side bar fertilization significantly reduced N loss by 0.466-0.673 kg(N)·hm^-2 due to surface runoff decreasing by 3.54%-29.36%, compared with T2 treatment. Side bar fertilization significantly increased N use efficiency. N use efficiency under T4 treatment was 1.70 and 1.22 times that of T2 and T3 treatments, respectively. High slow-release fertilizer plus side bar application was the best fertilization mode in the study area. Our results were beneficial for improving productivity efficiency in agricultural, resources and environmental protection.