In order to deeply understand organic nitrogen (N) components and transformation properties of farmland soil during non-growing season, with a laboratory simulation experiment, the dynamics of organic N components in the cultivated black soil were investigated under different freezing-thawing conditions (freezing-thawing temperature, freezing-thawing frequency, water content) by the Bremner N classification method. The results showed that freezing-thawing cycles (FTCs) had significant influence on organic N fractions and transformation process of cultivated black soil, and ammonia N and amino acid N were the main components of soil acid-hydolyzable organic N. With freezing temperature decreasing, amino acid N content significantly increased, ammonia N and unknown N contents significantly decreased, and the changes of amino sugar N content differed from thawing temperature. With thawing temperature increasing, the fractions of acid-hydolyzable organic N changed with no rule. With freezing-thawing frequency increasing, amino acid N content significantly decreased, unknown N content significantly increased, ammonia N content first increased then decreased, and amino sugar N content changed with no rule. With water content increasing, the contents of ammonia N and unknown N in the FTCs-treated soil both increased significantly being contrary to the changes of amino acid N, and amino sugar N content changed in a no rule. Therefore, it is preliminarily concluded that larger freezing-thawing amplitude, suitable freezing-thawing frequency and water content were the major factors affecting organic N transformation of farmland black soil. FTCs could enhance the contents and proportions of ammonia N and amino acid N in acid-hydolyzable organic N, increase soil mineralizable N content, promote soil N transformation, and was beneficial to the accumulation of soil available N, which could provide abundant nutrients for crop growth in spring.