The invention discloses a CAN bus redundancy retransmission fault-tolerant communication method. The method comprises the steps that a main node sends data to a target slave node through a first bus channel in an application layer; if communication is unsuccessful, the main node carries out data retransmission in a current bus channel; if the communication is unsuccessful again, the current bus channel is switched to a second bus channel for data retransmission, and so on, thereby finishing one-time data communication. In the communication process, according to the method, a data retransmission principle, a bus channel selection and switching principle, a bus redundancy retransmission fault-tolerant principle and a redundancy retransmission protection principle are reflected. According to the method, on the premise of not changing a hardware design and a basic protocol thereof, through utilization of two hot-redundant bus channels, the redundancy retransmission fault-tolerance for a CAN bus in the application layer can be realized, and the relatively high stability for data communication of a single-host multi-slave large ground measurement and control system is provided.