The present invention relates to a method and apparatus for transmitting a CAN frame. A method for transmitting a CAN frame includes receiving an input of a transmission file containing a plurality of CAN frames; detecting the number of the CAN frames contained in the transmission file; comparing the number of the CAN frames with the number of transmission buffers; mapping, when the number of the CAN frames is less than or equal to the number of the transmission buffers, the CAN frames onto the transmission buffers in a one-to-one mapping manner; and mapping, when the number of the CAN frames is greater than the number of the transmission buffers, the CAN frames onto the transmission buffers in a many-to-one mapping manner.