In this paper,we used the extremely limited valuable seismic data,and fully exploited the available information in the concise description of the earthquake,to screen and parameterize two early moderate-strong earthquakes in Jiangxi Province based on comprehensive literature and history records,human history,and earthquake research results. We concluded that the Jishui-Yongfeng earthquake in A.D.304 are located at 27.3°N and 115.3°E with the magnitude of M_S5. The Yugan earthquake in A.D.455 are located at 28.7°N and 116.7°E,with the magnitude of M_S5 1/2. This work can provide new information for the historical earthquake research and the division of potential source areas in Jiangxi Province.