A multiway switch, a radio frequency system, and a communication device are provided. The multiway switch is configured to be coupled with an antenna system and a radio frequency circuit. The multiway switch has eight T ports and four P ports. The eight T ports include two first T ports, and each of the two first T ports is coupled with all the four P ports. The antenna system includes four antennas corresponding to the four ports. The multiway switch is configured to implement a function of transmitting a sounding reference signal (SRS) through the four antennas in turn.