Abstract: 【Objective】An investigation was carried out for a better knowledge to fern flora on the southern branch of Ningzhen Mountains in Nanjing and analysis of ferns in garden application.【Method】We counted fern species on the southern branch of Ningzhen Mountains with a case of Jiangjun Mountain by the methods of wild investigation, specimen collection and indentification, meanwhile we analyzed fern flora composition, areal-types and compared integrative coefficient, similarity coeffiecient and species richness of the flora and other floras,and finally we analyzed ferns ecological types in the flora as well as their application in garden.【Result】There were a total of 33 fern species belonging to 24 genera and 19 families in the flora, whose integrative coefficient was 0.442, and species richness index was 25.54,which was the maximum. The dominant family consisted of Thelypteridaceae, while there was no dominant genera in this flora, which was ancient and relic. The flora was closely related with Longwang Mountain in Zhejiang and Yuntai Mountain in Jiangsu, and less closely related with Huangshan Mountain in Anhui and Gaoleshan Mountain in Zhejiang and distant with Lushan Mountain in Jiangxi. According to the habitat and distribution of ferns in the flora, they can be divided into hydrophytes, lithophytes and terrestrial.【Conclusion】The fern resourecs in Jiangjun Mountain was relatively abundant, and the flora occupied an characteristic of transition from subtropical to temperate zone, and the areal-type of East Asia possessed a main advantage in the flora. Additionally, ornamental ferns were relatively abundant in the flora, but many of species with high ornamental value and application prospects still have not been recognized and exploited.