Abstract: A field experiment was conducted to study the effects of different nitrogen forms ((NH₂)₂CO_N, NO₃^--N, NH₄⁺-N, and NO₃^--NH₄⁺) and their ratios on the yield formation, quality, and nutrient (N, P, and K) absorption of broccoli (Brassica oleracea). Fertilization with NO₃^--N increased the accumulation of nitrate and soluble sugars in ball flower. When the NO₃^--N:NH₄⁺-N ratio was ranged from 3:7 to 5:5 and from 5:5 to 7:3, respectively, the accumulation of nitrate in the ball flower was reduced, while the soluble sugars content was promoted. Fertilization with (NH₂)₂CO_N and NH₄⁺-N was conducive to the improvement of Vc content in the ball flower. N fertilization increased the accumulation of N, P, and K in plants, with the highest contents of N, P, and K observed at rosette stage. Throughout the entire growth period, NH₄⁺-N fertilization improved the plant N content, whereas NO₃^--N fertilization improved the plant K content. At different growth stages, the effects of different N sources on plant P content varied. As compared with applying single N forms, the NO₃^--N:NH₄⁺-N ratio ranged from 3:7 to 5:5 could improve the yield significantly. It was suggested that a combined application of NO₃^--N and NH₄⁺-N with an appropriate ratio could improve the productivity, quality, and economic return of broccoli.