The invention provides a 400 kHz and 800 MHz hybrid communication device and a 400 kHz and 800 MHz hybrid communication method. The device comprises a first sending and receiving machine (100), a second sending and receiving machine (200) and a controller (300), wherein the first sending and receiving machine (100) and the second sending and receiving machine (200) send and receive wireless data and characteristic information at the frequencies of 400 kHz and 800 MHz respectively and work simultaneously; and the controller (300) is electrically connected with the first sending and receiving machine (100) and the second sending and receiving machine (200) and is used for selecting effective wireless data from the wireless data received by the first sending and receiving machine (100) and the second sending and receiving machine (200) according to the effectiveness of the characteristic information received by the first sending and receiving machine (100) and the second sending and receiving machine (200). The device performs data communication by adopting two sending and receiving machines with different frequencies, thereby guaranteeing the reliable wireless data communication under the condition of not arranging communication reinforcement equipment along a railway, and saving the cost for arranging the communication reinforcement equipment.