Net mineralization of N in 16 soil samples in cluding three types of soil (loessal soil,cinnauwn soil and fluvo-aqruuc soil) was determined over 154-day period at 35℃, using incuhartion intervals of 7, 7, 14, 28, 28, 28, 42 days. For most soils, cumnlatirve net N mineralized is linearly related to the srluare root of time, t^1/2. The N mineralization potential, No, of each soil was calculated by the mathematical models of G, Stanford and S.J. Smith, and J. Richter, using the data, derived from the incubatian experiment. The results obtained indicated that the N mineralization potential, N₀, could reflect N-sup-paying capabilities of soils;the No constituted 10.8-23.4% of total N in soil;the constant of N mineralization rate, k, averaged 0.0064±0.0006 day^-1.