Based on analysis of feasibility, pros and cons of domestic and foreign existing micro turbofan configurations, a novel configuration with compact and compound compression system is put forward, in order to reduce fuel consumption effectively while keeping the structure simplified and compact. In this scheme, the fan rotor and the mixed flow compressor rotor compose tandem blades. Through the research of independent mechanism and coupling mechanism of tandem blades, it is thought that fine design of tandem blades (tandem totally or partially) can significantly improve the compression performance. By establishing overall performance model and analyzing parameters, it is revealed that specific fuel consumption could be 24.4% lower than corresponding micro turbojet engine approximately. The rotor of composite compression system is then preliminarily designed and numerically simulated, and it is obtained that the pressure ratio is 5.2 and the efficiency is 91% down the bypass, while 1.6 and 84% in the bypass, of the compound compression system. With flow field analysis, it is indicated that compound compression system both down the bypass and in the bypass can complete the compression in high efficiency.