In order to further elucidate the effects of different water and nitrogen regulation models on the accumulation of ammonium and nitrate in different soil layers and the effectiveness of soil nitrogen in the black soil region of cold area, based on field plot experiment and 15N tracing microzone test, the inorganic nitrogen and NH+415N and NO-315N accumulations of nitrogen in soil profiles under different water and nitrogen regulation models were studied, and the effect of different water and nitrogen regulation models on soil nitrogen availability was calculated according to the results of isotopic determination. The results showed that the accumulation of soil inorganic nitrogen and fertilizer nitrogen with inorganic nitrogen form residue in the soil profile was increased with the increase of nitrogen application and decreased with the increase of soil depth in two irrigation modes under controlled irrigation and conventional irrigation. The accumulation of inorganic nitrogen and nitrogen in the form of inorganic nitrogen in surface soil (0~20cm) of paddycontrolled irrigation mode under different nitrogen application rates was higher than that of conventional irrigation. The total amount of inorganic nitrogen and NO-315N in 20~40cm and 40~60cm soil layers was lower than that of conventional irrigation, and the accumulation of NH+415N in 40~60cm soil layer under low nitrogen fertilization between two irrigation modes was not significant (P>0.05). The NO-315N accumulation of 20~40cm soil layer in conventional irrigation mode at the same nitrogen application rate was 10~11 times than that of controlled irrigation mode. The NO-315N accumulation of 40~60cm soil layer was nearly three times higher than that of control irrigation mode. Totally 77.77%~84.51% of the accumulation of nitrogen under ricecontrolled irrigation mode at different nitrogen application rates was from soil nitrogen, which was 12.91%~23.12% higher than that under conventional irrigation, and the “A” value expressing soil nitrogen availability in ricecontrolled irrigation mode under the same nitrogen application was increased by 9.41%, 5.65% and 3.69%, respectively. Compared with conventional irrigation, the ricecontrolled irrigation mode can effectively improve the nitrogen efficiency of paddy soil, reduce the leaching loss of fertilizer nitrogen, and play an important role in saving water and reducing emissions, and the research results can provide a reference for the formulation of reasonable water and nitrogen control measures in the black soil area.