The invention discloses a current amplifying device based on a full-bridge switch tube. The device comprises a current amplifying module, a control module and a signal transmitting module. The currentamplifying module comprises a supporting capacitor group, a full-bridge switch group, a multi-stage LC filter and a PWM output isolation driver connected in order. The multi-stage LC filter is connected to a load. The control module comprises a control IC unit, a current sampling unit and a protection unit. The load is connected to the control IC unit through the current sampling unit and the protection unit, and the control IC unit is connected to the full-bridge switch group through the PWM output isolation driver. The signal transmitting module comprises a control power input, a DA signalinput, an AD signal output and a fault signal output respectively connected to the control IC unit. In the invention, after the current is amplified, the power can be made to be large, harmonic signals are few, the signals are relatively clean, the voltage of the full-bridge switch group is more stable, the damage rate of the switch tube can be effectively reduced, and the service life is improved.