In order to explore nitrogen (N) output characteristics in double-rice cropping field during the process of the typical natural rainfall runoff, the long-term experiment with common urea (U) and reduction of controlled-release urea (CRU) was conducted to study the dynamics of total nitrogen (TN), ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) loss and loss ratio of runoff in paddy field. The results showed that N loss peaked in the early time of fertilization, which was the critical period to control N loss. NH₄⁺-N was the main form of N-applied treatments to runoff during early and late rice season, accounting for 64.5%~66.3% and 61.0%~68.6% in TN loss, respectively. The TN loss and loss ratios of runoff in U treatment during early and late rice season were 5.6 kg/hm² (2.2%), and 5.0 kg/hm² (1.7%), respectively. Compared with U treatment, TN loss in CRU treatments were reduced by 17.4%~34.1% and 17.3%~37.7%, and the TN loss and loss rates of runoff decreased with the decrease of N fertilizer rate. N loss in early rice season was higher than that in late rice season, and the inhibition of CRU treatments in N loss in late season rice was better than that of early rice season as affected by rainfall intensity. TN loss and grain yield in CRU treatments for earlyseason, late-season rice and the continuous cropping cycle had significant linear relationships with N fertilizer rate, which increased with the increasing N fertilizer rate. In conclusion, U treatment significantly increased N concentration and the ratio of NH₄⁺-N to TN in runoff. CRU effectively reduced N release rate and N loss in the early time of fertilization, and thus increased grain yield. The findings indicate that the reduction of CRU is helpful for further control of N loss risk in paddy field, and promote the reduction of agricultural non-point source pollution, especially in reduction of 10% N treatment.