The present invention discloses a switchable frequency response microwave filter, which uses voltage-controlled varactors to attain the separation or combination of the odd mode and even mode of signals in a dual-mode ring resonator to realize a bandpass or bandstop function and then controls the frequency response of the output filtered signals. Further, the present invention integrates different circuit architectures having bandpass and bandstop functions into a single circuit to reduce the complexity of the circuit.