Tunable optical filter based on two-dimensional heterostructure photonic crystal is formed by curved waveguides and neighboring cavities when line and dot defects are introduced into heterostructure photonic crystal. Finite-difference time-domain (FDTD) method is used to analyze the filter. Results showed that the waves with certain frequencies in the waveguide could be introduced into the cavity when resonance coupling occured. The introduced frequency depends on parameters of curved waveguide and cavities in the heterostructure photonic crystal. When the refractive indices of neighboring medium or radius of the rods were changed, a wide transmission region of 31 nm or 12 nm could be realized respectively. Our results provided a new design method and bases improving the efficiency of add/drop and realizing the tunability of filter.