Abstract: By using in situ leaching device, a field experiment was conducted to study the nitrate leaching amount and density at 60 cm soil depth, nitrate accumulation in soil profile(0-80 cm)of poplar-wheat intercropping ecosystem. Four treatments were installed, no fertilization(N₀,0 kg/hm²),conventional fertilization(N₁₄₀,140 kg/hm²),reduced N application(N₇₀,70 kg/hm²),increased N application(N₂₁₀,210 kg/hm²). The results indicated a positive correlation between quantity of leachate water and precipitation, the poplar-wheat intercropping ecosystem can reduce the quantity of eluviate solution. The nitrate leaching loss increased according to the increasing N fertilization rate. In treatment spot N₂₁₀, the nitrate nitrogen loss from N fertilization at 60 cm soil depth was the greatest(13.89 kg/hm²), it declined by 60.27% and 50.11% in poplar-wheat intercropping ecosystem away from the poplar row 0.5 m and 1.5 m, respectly. The nitrogen leaching and accumulation were significantly lower in poplar-wheat intercropping ecosystem, and variances of the distribution for soil nitrate nitrogen were significant.