The effects of nitrogen management on yield, quality, nitrogen and dry matter accumulation and transportation of watermelon in sand field were studied based on a field experiment. The results showed that too low or too high basal nitrogen fertilization was unfavorable to seedling growth of watermelon in sand field, and no nitrogen application at vine extension or fruiting stages limited the formation of ‘source’ or ‘sink’. At the same nitrogen rate, compared with the traditional T₁ treatment (30% basal N fertilizer + 70% N fertilizer in vine extension), the nitrogen and dry matter accumulation of vegetative organs of T₄ treatment (30% basal N fertilizer + 30% N fertilizer in vine extension + 40% N fertilizer in fruiting) and T₆ treatment (100% basal N fertilizer + NAM) were reduced significantly, but the nitrogen and dry matter accumulation of fruit were increased significantly in the flushing period. The nitrogen transportation ratio and nitrogen contribution ratio of T₄ were 33.6% and 12.0%, respectively. Compared to T₁, the nitrogen harvest index, nitrogen fertilizer partial factor productivity and nitrogen fertilizer recovery efficiency of T₄ and T₆ treatments increased by 14.1% and 12.7%, 11.6% and 12.5%, 5.3% and 8.7%, respectively, and yield of watermelon increased by 11.6% and 12.5%, the soluble sugar, effective acid, the ratio of sugar and acid, Vc content increased by 16.5% and 11.7%, 4.5% and 2.8%, 19.4% and 13.4%，35.6% and 19.0%, respectively. Therefore, T₄ and T₆ treatments were the optimal nitrogen fertilizer management mode which could not only achieve high yield and quality but also obtain high nitrogen fertilizer use efficiency in sand field. T₆ treatment was the best nitrogen fertilizer management mode considering reduction of fertilizing labor intensity and extending service time of gravelmulched field.