The present disclosure provides a microwave transmission apparatus. The microwave transmission apparatus includes a waveguide, configured to transmit microwaves emitted from a microwave source to a load; and an impedance matching structure, disposed in the waveguide the waveguide. The waveguide includes a microstrip interdigital capacitor. The impedance before the input end of the impedance matching structure is matched with the impedance after the input end of the impedance matching structure by adjusting an equivalent capacitance formed by the microstrip interdigital capacitor and/or a position of the microstrip interdigital capacitor along the extending direction of the waveguide.