Based on the specific motion features of coaxial rigid rotor, the complex unsteady aerodynamic characteristics caused by the great difference on airloads of the advancing side and retreating side are analyzed and some particular aerodynamic problems including lift?offset, rotor?to?rotor interactions and hub drag are summarized. Focused on the special aerodynamic problems of coaxial rigid rotor, the recent research progresses on aerodynamic theory, aerodynamic configuration optimization design and corresponding experiments are reviewed. Finally, the further development direction and research priorities on coaxial rigid rotor aerodynamics are pointed out considering the bottlenecks which exist in current studies.