The invention provides a redundant high-safety CAN (controller area network) bus communication system and a communication method thereof. The system comprises an upper computer, multiple lower computers and two CAN buses being hot standby of each other; each upper computer and each lower computer are formed by modules being the hot standby of each other; each module is provided with two synchronously operated microprocessor CPUs (central processing unit) comprising a first CPU and a second CPU, and two mutually independent operation passages are formed; two CAN bus interfaces are integrated at each operation passage; the two CAN bus interfaces are respectively correspondingly connected with the two CAN buses. The invention also provides a communication method of a redundant high-safety CAN bus communication system. Multi-verification and redundant transceiving technologies are adopted, the sending and receiving of each data packet are redundant, verification for multiple times is performed at a sending end and a receiving end, and high-safety is ensured.