In order to explore the effects of corn-straw biochar on the migration and retention characteristics of nitrate nitrogen in soil, this study selected brown soil and black soil in Northeast China as tested materials, different proportions of corn-straw biochar (1%, 5%, and 10%) were added to soils for a soil column leaching test to simulate the leaching process of nitrate nitrogen in soils, the volume of leachate, the content of nitrate nitrogen in leachate and the vertical distribution of nitrate nitrogen in soil columns were measured. The results showed that biochar significantly affected the total leachate outflow and soil permeability coefficient, both decreased with the increase of biochar addition. With the increase of leaching time, the outflow of nitrate nitrogen in soil first increased, then decreased, and finally gradually stabilized (except for brown soil added with 10% of biochar, black soil added with 5% and 10% of biochar). Under the same ratio of biochar addition, the total amount of nitrate nitrogen outflowed from brown soil was much higher than that from black soil. The total amount of nitrate nitrogen outflow was positively correlated with leachate volume and soil permeability coefficient. After the leaching test, part of nitrate nitrogen remained in the soil, for brown soil with biochar added, most of nitrate nitrogen was trapped in the upper soil, nitrate nitrogen content showed a trend of higher in the top layer and lower in bottom layer, but for the black soil with biochar added, not significant affect was observed in the distribution of nitrate nitrogen in different layers. In conclusion, the addition of corn-straw biochar can significantly reduce soil permeability, hinder water migration, and reduce the risk of nitrate nitrogen leaching in soil, which is of great significance for improving nitrogen utilization and protecting environment.