The present invention provides a harmonic suppression system, including: an interface connector, a baseband chip, an antenna, an antenna switch, at least two LC trap networks, a first differential SPMT switch, and a second differential SPMT switch, where the interface connector is connected to a common end of the first differential SPMT switch; a control port of the first differential SPMT switch is connected to a control port of the second differential SPMT switch, and a gating throw end of the first differential SPMT switch is separately connected to one end of each LC trap network in a one-to-one correspondence; the control port of the second differential SPMT switch is connected to the baseband chip, each gating throw end of the second differential SPMT switch is separately connected to the other end of each LC trap network in a one-to-one correspondence, and a common end of the second differential SPMT switch is connected to the baseband chip; the baseband chip is connected to the antenna switch; and the antenna switch is connected to the antenna.