The invention discloses a general multi-mode information processor for aircrafts based on software radio. The multi-mode information processor comprises a main control module, a radio frequency module, and a signal processing module. The main control module sends a relay mode selection instruction and a direct mode switching instruction to the signal processing module and the radio frequency module. The signal processing module and the radio frequency module load different executable programs and perform switching between different radio frequency channels according to the relay mode selection instruction, and support two types of relay satellites of different signal systems in carrying out relay communication. According to the direct mode switching instruction, direct communication between an aircraft and ground tracking telemetry control equipment or communication between an aircraft and a relay satellite is supported. The availability and robustness of the information processor are improved, the generality of the information processor is improved, and the development cycle is shortened.