The invention relates to a variable frequency superconducting microstrip line resonator, which comprises an upper-layer superconducting resonator structure, a lower-layer superconducting thin film and a dielectric substrate positioned between the upper-layer superconducting resonator structure and the lower-layer superconducting thin film. The variable frequency superconducting microstrip line resonator is characterized in that: the upper-layer superconducting resonator structure comprises a continuous main strip line, one or more external microstrip lines and one or more switches; one or two ends of the main strip line form an interdigital coupled structure with the one or more external microstrip lines; the interdigital coupled structure is formed by intersecting the port comb crotch structure of the main strip line and the port comb crotch structure(s) of the one or more external microstrip lines, and the port comb crotch structures of the main strip line and the one or more external microstrip lines do not contact each other; the external microstrip lines are grounded through the switches; and the grounding state, off state or state combinations of the one or more external microstrip lines are controlled by the one or more switches to change the resonance frequency of the resonator. The variable frequency superconducting microstrip line resonator has the advantages of high quality factor, wide variable frequency range, a great number of variable frequency points and frequency control accuracy, is easily made, and can be used for designing and manufacturing high-performance variable frequency band-pass, band elimination, high-pass, low-pass and multi-band superconducting filters.