The invention discloses a system and a method for carrier and wireless physical layer fusion based on signal-to-noise ratio optimization, wherein the system for carrier and wireless physical layer fusion based on signal-to-noise ratio optimization comprises a sending digital baseband signal processing module, a digital-to-analog conversion module, a wireless sending analog front end, a carrier sending analog front end, a wireless receiving analog front end, a carrier receiving analog front end, an analog-to-digital conversion module, a receiving channel selection module, a signal-to-noise ratio estimation and comparison module and a receiving digital baseband signal processing module. In the method for carrier and wireless physical layer fusion based on signal-to-noise ratio optimization of the invention, a uniform signal system is used for the carrier and the wireless at a physical layer, the carrier and the wireless are sent simultaneously or at different time at a sending end, two types of the communication signals at a receiving end are detected simultaneously, and one path with relatively higher signal-to-noise ratio is selected to be demodulated and decoded. Whereby, a problem of time synchronization and a problem of being liable to leave packets and lose packets caused by the need of channel switching are avoided.