This paper proposed a dual-band film bulk acoustic resonator (FBAR) filter design method based on the wideband branch matching. Based on S-parameter network impedance transformation theory, the principle of broadband matching at the input and output terminals of the filter network is analyzed, and impedance matching branches corresponding to the two FBAR filter bands is designed. Then, the dual-band FBAR filter is constructed by connecting the common terminals of the two filtering networks. The capacitance and inductance of the matching network can be accurately designed on substrate, and the integration of the dual-band filter can be realized by mounting the two FBAR filters on the substrate. Finally, a dual-band filter with center frequencies of 2 492 MHz and 6 000 MHz is designed, fabricated and tested. The test results show that the insertion loss of the two bands are 3.29 dB and 4.91 dB respectively, and the stopband suppression is less than -25 dB, which is in good agreement with the theoretical ones.