A harmonic suppression system, including an interface connector is connected to a common end of a first differential SPMT switch; a control port of the first differential SPMT switch is connected to a control port of a 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 a 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 an antenna switch; and the antenna switch is connected to a antenna.