The invention discloses a fast-response soft-switching isolation inverter and a method, and belongs to the field of inverters. The device comprises a direct current input circuit, a direct current filter circuit, a buffer resonant circuit, a high-frequency conversion circuit, a fast response inversion circuit, an output low-pass filter circuit and a load circuit; the direct current input circuit is sequentially connected with the direct current filter circuit, the buffer resonant circuit, the high-frequency conversion circuit, the fast response inversion circuit, the output low-pass filter circuit and the load circuit, the load circuit is connected with an MCU control circuit through a first sampling circuit, and the MCU control circuit is connected with the fast response inversion circuitthrough driving circuits of switch tubes Q2 and Q3 and connected with the high-frequency conversion circuit through a driving circuit of a switch tube Q1. The method comprises the steps that on the original edge of a high-frequency transformer, the voltage and current of the power switch tube Q1 are both changed into zero in an LC resonant mode when the power switch tube Q1 is switched on and switched off, the soft switching action state of the power switch tube Q1 is kept, and the switch-on and switch-off losses of the power switch tube Q1 are reduced; on the subsidiary side of the high-frequency transformer, by controlling the power switch tubes Q2 and Q3 to be switched on and switched off, compared with existing inverters, the inverter has the advantages of being low in circuit loss, fast in load instantaneous response, high in intelligentization degree and low in cost.