This paper is focused on the properties of modified domestic polyaramid fiber(F-3A) and F-3A fiber reinforced epoxy composites (F-3A/ epoxy), which is studied on the background of prepareation of F-3A fiber and application of F-3A/ epoxy composite. The composite was prepared by F-3A fiber and a kind of new epoxy resin system, the properties of unidirectional NOL ring composite and full scale composite structures were studied. The results show that the mechanical properties and process performance of F-3A fiber are excellent, the fiber can be used as high performance reinforcements in advanced composite fields.