In this paper, a novel hexagonal CSRR (complementary splitring resonators) structure is proposed, and a SIW (substrate integrated waveguide) dualband filter is designed. By adjusting the size of the four sets of CSRR clamp ring, the two resonant frequencies can be controlled. The first passband and the second passband of the filter are respectively formed by a hexagonal CSRR clamp ring with different sizes of up and down two layers, and can control the position of the frequency points independently. This design uses four node topology, through the cross coupling to form the two transmission zeros, forming a high stopband suppression characteristics. The two frequency points of the filter are 2.4 GHz and 5.2 GHz, and the relative bandwidth is 8% and 5%, respectively. The utility model can be widely used in the RF receiver frontend system of the wireless communication field, and has the characteristics of miniaturization, low loss and easy processing.