Accumulation of NO₃-N in deep layers is the unique of N cycle in rained farmland in the arid and semi-arid areas. Based on the long-term experiment, the effects of fertilization, crop, rainfall, tillage systems, rotation, and soil properties on the NO₃-N accumulation were reviewed. The over application of nitrogen fertilizer and the precipitation of 400~800 mm mainly contributed to the NO₃-N accumulation in the 100~300 cm depth. The NO₃-N accumulation in the 100~300 cm depth was increased with the increase of N rates, fertilizer N incorporation with phosphate fertilizer could reduce the NO₃-N accumulation. The nitrogen usage efficiency also affect NO₃-N accumulation due to N uptake by crops, crop rotation and fallow crop could reduce the NO₃-N accumulation. NO₃-N accumulation was mainly developed in the soils with heavy texture. The clay mineral with large positive charge mainly contributes to NO₃-N accumulation in the tropical soils. The further research emphases about the NO₃-N accumulation in the deep depth were put forward as follows: bio-availability, transport in soil profile under rain fed or irrigation, the relation to crop root distribution and growth, and the effect of the NO₃-N accumulation on soil properties and soil gas.