Abstract: Effect of lignin isolated from black liquor of pulping process on N,P transformation in soil and corn yield has been determined. Results show that lignin can inhibit oxidization of NH₄⁺to NO₃^-,and the inhibiting effects increase with concentration.Both (NH₄)₂HPO₄ and (NH₄)₂SO₄ treatments are more effective for inhibiting nitrification than urea treatment when lignin is applied.Urea plus 2% and 5% lignin can reduce N₂O emissions by about 83% and 96%, respectively,while(NH₄)₂HPO₄ plus 2% and 5% lignin can respectively reduce N₂O emissions by 83% and 93%(30℃).Water-solubility P content in soil increases when lignin is applied.The results of potted test show that corn growth is better at lignin treatment than at non-lignin treatment.Lignin accelerates corn root and height growth.At concentrations of 50μg/g and 200μg/g,lignin increases corn yield 4.2% and 18.8%,respectively.