The present invention relates to a wireless car digital AV system to be applied in a car, and the wireless car digital AV system comprises an AV Host and at least one or multiple display devices. The AV Host includes a storage device and a wireless network interface, and the storage has at least one digital AV file. The display device includes a wireless network interface and a display panel. The display device is connected to the AV Host by the wireless network interface, such that the display device can receive and play the digital AV file transmitted from the AV Host through the wireless network interface. Furthermore, the present invention also discloses a method for an automobile AV Host to wirelessly transmit a video file to a display device.