Abstract: Taking the Zhaojinggou tantalum-niobium ore in Inner Mongolia as the research object, the main mineral compositions and the relevant content of raw ore are determined by optical microscope, artificial heavy sand, X-ray diffraction and electron probe analysis. The chemical composition, particle size and embedded features, as well as the occurrence state of tantalum, niobium and other elements are also studied in detail. Tantalum and niobium manganese minerals have fine grain sizes, usually in the range of 0.02—0.074 mm. Inclusion form is the main distribution state, and accounting for 66.83%. Valuable minerals include two mineral subspecies, namely tantalum-niobium manganese ore and niobium-tantalum manganese ore. The tantalum-niobium manganese ore is rich in iron or manganese with a certain content of titanium. According to the results of metal balance, the tantalum and niobium are mainly concentrated in tantalum-niobium manganese ore, and dispersed in gangue minerals such as mica, feldspar and quartz. The concentration coefficient of Nb₂O₅ is 61.23%, and that of Ta₂O₅ is 57.17%. Based on this study, a reasonable process of ore dressing process has been made, and good dressing indexes have been obtained.