In order to deeply understand nitrogen (N) transformation process in farmland soil during non-growing season, with a laboratory simulation experiment, the effects of different freezing and thawing temperatures and freezing-thawing cycling frequencies on the contents of soil dissolved N components were investigated in four typical farmland soils (brown soil, cinnamon soil, meadow soil and black soil). The results showed that with freezing temperature decreasing, the contents of nitrate N (NO₃^- -N), ammonium N (NH₄⁺-N), dissolved organic N (DON) and dissolved total N (DTN) all increased significantly in four farmland soils. With thawing temperature increasing, the dynamics of soil NO₃^- -N, DON and DTN in four farmland soils were synergistically affected by freezing temperature and soil type, except for NH₄⁺-N content increasing significantly. With freezing-thawing cycling increasing, the contents of NO₃^- -N, NH₄⁺-N, DON and DTN all increased significantly in brown soil and cinnamon soil; the contents of NO₃^- -N, DON and DTN all increased significantly, and NH₄⁺-N content decreased significantly in meadow soil; the contents of NO₃^- -N and NH₄⁺-N both increased significantly, and DON and DTN contents both first increased then decreased in black soil. As affected by freezing-thawing, the response capacity of tested soils differed from soil type, with following as cinnamon soil＞brown soil, meadow soil＞black soil. Therefore, it is preliminarily concluded that freezing-thawing cycling could promote soil N transformation, and was beneficial to the accumulation of soil available N, which could provide abundant nutrients for crop growth in spring but might also increase the risk of soil N loss at the same time.