The application and regulation effects of adding biochemical inhibitors and biostimulant humic acid to the high efficiency and stability urea on fertilizer nitrogen transformation in black soil were studied to provide a theoretical basis for the study of the special formulation of high efficiency and stability urea combined with biostimulant humic acid and biochemical inhibitor in the black soil.A pot experiment was conducted with 9 treatments，blank (CK)and urea (N)were set up as controls，and humic acid (H)，N-butyl thiophosphate-triamine (NBPT)，3，4-dimethyl-pyrazolate phosphate (DMPP)and 2-chloro-6-trimethyl-pyridine (CP)and their combinations were added to urea fertilizer，respectively.The effects of urea fertilizers with different biochemical inhibitors and humic acid on soil available nitrogen contents，biological index and yield of maize were determined，and the nitrification inhibition rate，grain nitrogen uptake，total nitrogen uptake，urea fertilizer use efficiency were calculated.The results showed that compared with urea alone treatment，the combined application of humic acid and biochemical inhibitors NBPT，DMPP and CP significantly increased maize yield，nitrogen uptake，nitrogen use efficiency，and had significant effects on soil available nitrogen contents(P<0.05).Compared with the application of biochemical inhibitor NBPT alone，urea with humic acid and NBPT addition significantly increased the nitrification inhibition rate of black soil in maize seeding stage，plant height and chlorophyll content by 14.03%，6.31% and 3.22%，but the maize yield，nitrogen uptake，nitrogen use efficiency，stems thickness and leaf area all decreased. Compared with the application of biochemical inhibitor DMPP alone，urea with humic acid and DMPP addition increased plant height and chlorophyll content by 7.97% and 20.17%，and significantly decreased the nitrification inhibition rate of black soil in maize seeding stage，maize yield，economic coefficient，grain nitrogen uptake，leaf area，total nitrogen uptake，urea fertilizer apparent utilization rate and stems thickness decreased(P<0.05).Compared with the application of biochemical inhibitor CP alone，urea with humic acid and CP addition significantly increased the maize yield，chlorophyll content，total nitrogen uptake，nitrogen use efficiency (P<0.05)，and the plant height，grain nitrogen uptake were also increased，but the stem thickness and leaf area were decreased(P<0.05).In conclusion，in black soil，urea with humic acid and CP addition could increase the maize yield，nitrogen uptake，plant height，chlorophyll content and urea fertilizer use efficiency.Urea with humic acid and NBPT，DMPP addition could decrease maize yield，nitrogen uptake，nitrogen use efficiency，which is not conducive to the increase of yield and the improvement of urea fertilizer use efficiency.In black soil maize planting area，it is suggested to combine humic acid and CP to make the new high-efficiency and stability urea to increase the maize yield and improve urea fertilizer apparent utilization rate，and avoid using humic acid with NBPT and DMPP.