In order to make soil N management more scientific, N fertilizer application more reasonable and soil N utilization rate of crops higher in Jiangxi Province, spatio-temporal variation of total N in farmland soil of Jiangxi Province from 1985 to 2012 was analyzed by means of the Inverse Distance Weighted interpolation(IDW) method, overlay analysis method and Fisher statistical method in GIS technology based on the large volumes of soil samples collected during the second national soil survey and the project of soil-test-based formulated fertilization. According to the standard of the second national soil survey, total N contents in the farmland soils of Jiangxi have 6 grades, i.e., Grade 1 (>2.0 g kg^-1), Grade 2 (1.51 to 2 g kg-^-1), Grade 3 (1 to 1.5 g kg^-1), Grade 4 (0.76 to 1.0 g kg^-1), Grade 5 (0.51 to 0.75 g kg^-1) and Grade 6 (<0.5 g kg^-1). Soils in Grade1 and Grade 2 are regarded to be high, in Grade 3 and Grade 4, moderate and in Grade 5 and Grade 6, low in total N. Results show that total N contents in farmland soils varied sharply between soils in 11 cities and between soils of different types temporally and spatially in both 1985 and in 2012; and on average the farmland soils of the whole province were all 1 grade higher in 2012 than in 1985. The soils of the high total N level in Jiangxi were mainly distributed in the southern part of Poyang Lake Plain, basins along the Zhe-Gan Railway and Jitai basin in 1985, and more extensively in the whole Poyang Lake plain, basins along the Zhe-Gan Railway, Jitai basin and Ganzhou basin in 2012. In 1985 the soils in Pingxiang were the highest in total N content, in Jiujiang the lowest and in Ganzhou the highest in spatial variability of soil total N content, while in 2012. the soils in Xinyu were the highest in total N content, in Jiujiang the lowest, and in Jiujiang, the highest in spatial variability. Compared with 1985, 2012 was 7.24% higher in total N content in paddy soil and the growth was particularly obvious in soils of the high N level while the areas of the moderate and low levels decreased. The paddy soils the highest in total N content were in Pingxiang in both 1985 and 2012 and the paddy soils the lowest, in Ji'an, Ganzhou and Jiujiang, in 1985 and in Yingtan, Ganzhou and Jiujiang in 2012. Total N content in upland soils increased rapidly in 2012 or on average by 43.88% over that in 1985 and the area percentage of upland soils high in total N increased from 7.38% in 1985 to 88.16% in 2012.