Located at the east segment of Central Asian orogenic belt, the Xingan block and the Songliao- Xilinhaote block were separated by the Hegenshan- Heihe suture. Likewise, Xingan block and Songliao block were separated by the Nenjiang fault subsequently. In the central segment of the Great Kinghan Range, these two structures overlap and are hardly to be distinguished. To investigate the structures of the Great Kinghan Range, we have acquired a 60- km- length gravity, magnetic and magnetotelluric coincident profile in Zhalantun- Arongqi area, Inner Mongolia, China. The 120000 Buguer gravity data in Zhanlan- Arongqi area were reprocessed. Through multiple geophysical fusions, seven important faults were inferred. Among them, the Pangjiajie fault, the Hongxing fault, and the Alunhe fault are deep faults, at least penetrating up to middle crust. In addition, two low- resistivity belts in the middle curst were revealed, among which, C2 anomaly is interpreted as Hegenshan- Heihe suture. By correlating with 125000 geological mapping data, the geophysical interpretation results were proven. The research outcomes are helpful to geological studies of crustal structures at the central- east Great Kinghan Range margin.