A vehicle network transmission method, wherein the vehicle network transmission method comprises the steps of: a first transmission device transmitting a first data signal to a second transmission device; determining by the second transmission device whether the second transmission device is located in a target area; retrieving a geographic location of the first transmission device by the second transmission device upon determining that the second transmission device is located in the target area; calculating, by the second transmission device, a signal transmission region (Ra) of the first transmission device according to a received signal strength; determining by the second transmission device whether at least one third transmission device (D3, D4) is located in the signal transmission region (Ra); wherein in the step of determining whether the at least one third transmission device (D3, D4) is located in the signal transmission region (Ra) further comprises: each of the at least one third transmission device (D3, D4) periodically transmits another data signal comprising the geographic location of the at least one third transmission device (D3, D4) to the second transmission device, the second transmission device stores the geographic location of the at least one third transmission device (D3, D4) in a table, and the second transmission device obtains the geographic location of each of the at least one third transmission device (D3, D4) by looking up the table; and wherein the second transmission device forwards the first data signal to the at least one third transmission device (D3, D4) upon determining that the at least one third transmission device (D3, D4) adjacent to the second transmission device in the target area is located outside the signal transmission region (Ra) of the first transmission device. a first transmission device transmitting a first data signal to a second transmission device; determining by the second transmission device whether the second transmission device is located in a target area; retrieving a geographic location of the first transmission device by the second transmission device upon determining that the second transmission device is located in the target area; calculating, by the second transmission device, a signal transmission region (Ra) of the first transmission device according to a received signal strength; determining by the second transmission device whether at least one third transmission device (D3, D4) is located in the signal transmission region (Ra); wherein in the step of determining whether the at least one third transmission device (D3, D4) is located in the signal transmission region (Ra) further comprises: each of the at least one third transmission device (D3, D4) periodically transmits another data signal comprising the geographic location of the at least one third transmission device (D3, D4) to the second transmission device, the second transmission device stores the geographic location of the at least one third transmission device (D3, D4) in a table, and the second transmission device obtains the geographic location of each of the at least one third transmission device (D3, D4) by looking up the table; and wherein each of the at least one third transmission device (D3, D4) periodically transmits another data signal comprising the geographic location of the at least one third transmission device (D3, D4) to the second transmission device, the second transmission device stores the geographic location of the at least one third transmission device (D3, D4) in a table, and the second transmission device obtains the geographic location of each of the at least one third transmission device (D3, D4) by looking up the table; and wherein the second transmission device forwards the first data signal to the at least one third transmission device (D3, D4) upon determining that the at least one third transmission device (D3, D4) adjacent to the second transmission device in the target area is located outside the signal transmission region (Ra) of the first transmission device.