The invention brings forward a vehicle redundancy heterogeneous line transmission network and a data transmission method thereof and belongs to the technical field of automobile electronic control. The line transmission network comprises a vehicle redundancy power supply, multiple same redundancy line transmission network nodes, one redundancy line transmission network gateway, and a redundancy heterogeneous network composed of a time triggering type FlexRay bus and an event triggering type CAN bus, wherein the redundancy line transmission network nodes and the redundancy line transmission network gateway are connected with the vehicle redundancy power supply; each redundancy line transmission network node is connected with the FlexRay bus and the CAN bus; and the redundancy line transmission network gateway is connected with the FlexRay bus, the CAN bus and an automobile CAN bus. The data transmission method of the network comprises internal transmission mode, external transmission mode and gateway mode data arbitration. Under normal working conditions, the network forms two data transmission channels by the CAN and the FlexRay buses so as to carry out bus data transmission, and when one data bus generates a fault, the other data bus can still perform data transmission normally.