In order to study the physiological growth characteristics of annual seedling of Jatropha curcas and explore the law of water and nitrogen transfer in the root soil of Jatropha curcas under three drip irrigation levels, 10 mm(W1), 20 mm(W2) and 30 mm(W3), and three nitrogen(urea) levels, 0 g(N0), 90 g(N1) and 180g(N3) pre tree were applied. The results showed that the coupling of water and nitrogen had significant(P<0.05) or extremely significant(P<0.01) effects on the plant height, stem diameter and biomass of Jatropha curcas with some interaction effects between them. Under W1 treatment, the growth and dry matter accumulation could be promoted by applying appropriate nitrogen fertilizer. The values of stem diameter, plant height and measured biomass of N1 were larger than those of the others treatments when only considering the N treatment, while for the irrigation condition, W2 group had larger values of stem diameter, plant height and measured biomass. Longitudinally, the mean water content achieved the peak in the middle layer(>20-40 cm) from the 2016 June and September root, followed by the deep layer(>40-60 cm) and the shallow layer(0-20 cm). The water distribution was more uniform across soil depths in June and September 2017. Under nitrogen treatment(N1, N2), the mass fraction of nitrate nitrogen in the deep soil layer in June 2016 increased over the increasing of irrigation level, and W3 treatment was more likely to lead to nitrate nitrogen leaching than W1 and W2 treatment. Horizontally, the mass fraction of nitrate nitrogen at the measuring point 10 cm away from the trunk was lower than that at the 30 cm away from the trunk. The horizontal distribution of water keeps the same distribution rule with nitrate nitrogen in June and September, 2016. In June and September, 2017, due to the diversion of Jatropha curcas fibrous roots, the horizontal distribution of water in the middle soil changed. Based on the study, we concluded that the treatment with 90 g per tree of urea and 20 mm of drip irrigation level was the optimal treatment for the growth of Jatropha curcas.