The purpose of this study was to screen out the appropriate mixing ratio of slow-controlled-release urea (CRU) and common urea (U) suitable for Zhangqiu onion-wheat, and to realize the high efficiency of one-time application of slow-controlled-release fertilizer. Field experiments were conducted to investigate the effects of different mixing ratios of CRU and U on yield, apparent utilization rate of nitrogen fertilizer, economic benefits and soil nitrogen of Zhangqiu onion-wheat. The results showed that compared with conventional fertilization, the total yields of onion and wheat in two seasons increased by 2.2%~6.0% and 4.3%~5.2% respectively in 50% CRU+50% U and 70% CRU+30% U treatments, and the nitrogen apparent efficency of 50% CRU+50% U and 70% CRU+30% U in spring onion season increased by 3.44~8.48, 2.74~3.77 pecentage point respectively, 50% CRU+50% U and 100% CRU in wheat season increased by 6.41~6.96, 3.00~6.98 pecentage point respectively. In spring onion season, 50% CRU+50% U and 70% CRU+30% U increased 10 783.93 and 5 823.04 yuan/hm² respectively; in wheat season, 50% CRU+50% U and 70% CRU+30% U increased 2 035.33 and 1 448.24 yuan/hm² respectively. The nitrate nitrogen content in 0-20 cm soil under 100% CRU and 70% CRU+30% U was higher than that in conventional application. The accumulation of nitrate nitrogen in 20-100 cm soil layer with slow-contrdled slow-release fertilizer was higher than that of conventional fertilization, and the higher the mixing ratio of slow-controlled-release fertilizer, the higher the retained nutrient content. Considering all the factors comprehensively, 50% CRU+50% U was the best ratio applied in Zhangqiu onion-wheat, followed by 70% CRU+30% U. These two ratios could achieve one-time application of slow-controlled release fertilizer, at the same time, improve the apparent efficiency of nitrogen fertilizer, increase economic benefits, and prolong the ability of soil to provide nitrogen.