The invention discloses a radio frequency reflected wave detection device, a wireless communication system and an antenna state detection method. The radio frequency reflected wave detection device comprises a power detector and a coupler. Radio frequency signals are connected with a first port in direct connection ports of the coupler. A second port is connected with a detected element corresponding to the coupler. A port in coupling ports of the coupler is connected with the power detector and is used for coupling and transmitting reflected wave signals to the power detector when the detected element generates the reflected wave signals. The power detector is used for detecting the reflected wave signals. According to the technical scheme provided by the invention, the reflected wave signals generated when a fault occurs in an antenna are detected, so whether a connection state of an antenna system is normal or not can be pre-detected, the antenna fault detection accuracy is improved, a communication fault occurring in a whole communication system resulting from antenna abnormity or damage can be avoided, and a link of a radio frequency front end transceiver can be effectively protected.