The invention relates to a low-loss adjustable band-pass filter based on characteristics of the left-handed, and belongs to the field of a microwave component. The low-loss adjustable band-pass filter has a sandwich structure of ferrite/dielectric/ferrite; the thickness ratio of the three layers is 1 to (0.01 to 3) to 1; the resonant coupling of the two ferrite layers can realize the microwave transmission band with the left-handed characteristics; an external magnetic field can be used for the real-time regulation and control of the working frequency range of the microwave transmission band;and the structural parameters can be changed to effectively adjust the width and the insertion loss of the transmission band. The adjustable band-pass filter has the advantage of ultra-low loss whichcan be as low as below 1 dB; the real-time regulation of the working frequency range of the microwave transmission band can be realized; and the width and the insertion loss of the transmission band depend on the structural parameters. The adjustable band-pass filter has the advantages of simple structure, convenient application, easy production and convenient maintenance.