Abstract:【Objective】Soil total nitrogen(STN)plays an important role in terrestrial ecosystems, and hence is of great significance to mitigating the greenhouse effect and water eutrophication. Any slight changes in the STN pool will pose an important impact on global climate. It is, therefore, essential to make a precise estimation of STN density and storage in the effort to optimize nitrogen fertilizer management. However, so far most of the studies on estimation of STN have been done based on medium or small scale soil maps, and few have been reported to be based on provincial level detail soil databases. Consequently this study on STN estimation based on a provincial level soil database may help implement agricultural sustainable development with data support, and design agricultural management strategies.【Method】In this study, based on the most detailed soil database of Fujian Province, consisting of 3 082 sampling profiles and a 1: 50 000 soil map, analyses were carried out of spatial distributions of STN storage and density in the surface soil layer(0 ～ 20 cm)and soil profile(0 ～ 100 cm), in the bulk soil of the main types of soils of the Province as well as in the soils of different administrative divisions of the Province. The pedological knowledge based method, i.e, PKB, was used to correlate soil attributes with soil spatial data. So the 1: 50 000 scale soil map consisted of 247 969 soil patches and 3 082 soil profiles. 【Result】Results show that Fujian province has a total of 12.08 x 106 hm2 of soils. The STN density in the surface soil layer and soil profile of the province was averaged to be 0.35 kg·m–2 and 0.97 kg·m–2, respectively, while the STN storage was 42.06 Tg and 116.83 Tg, respectively. Analysis of the soils by prefecture shows that Nanping City was the highest, being 0.40 kg·m–2 and Longyan followed, being 0.39 kg·m–2 in STN density in surface soil, whereas Nanping City was the highest, being 1.19 kg·m–2 in and Sanming City followed, being 1.11 kg·m–2 in STN density in profile soil. Zhangzhou City was the lowest, being 0.24 kg·m–2 and Xiamen City the next, being 0.27 kg·m–2 in STN density in surface soil, whereas Zhangzhou City was the lowest, being 0.67 kg·m–2 and Putian City the next, being 0.71 kg·m–2 in STN density in profile soil. In terms of soil type, Mountain meadow soil was the highest, being 0.85 kg·m–2 and Skeletal soil followed, being 0.57 kg·m–2 in STN density in surface soil, whereas Mountain meadow soil was the highest, being 2.09 kg·m–2 and Yellow soil followed, being 1.27 kg·m–2 in STN in profile soil. Aeolian soil was the lowest, being by 0.11 kg·m–2 and Latosolic red earth the next, being 0.17 kg·m–2 in STN density in surface soil, whereas Aeolian soil was the lowest, being 0.27 kg·m–2 and Latosolic red earth the next, being 0.53 kg·m–2 in STN in profile soil. 【Conclusion】Consequently, the STN density in the surface and profile soil of Fujian demonstrates a declining trend from north to south, and from inland to coastal area, too. To sum up, the STN in Fujian Province varies significantly in spatial distribution. The findings in this study may be helpful in designing agricultural management strategies and controlling non-point source N pollution in the province.