By introducing defects and dispersion medium,a kind of compression［A(BC)］m structure of photonic crystals is studied.It has negative refractive index.TE wave and TM wave propagation and band gap characteristics are analyzed.It is shown that dispersion properties of the two modules change with the incident angle and refractive index of the dispersion medium,Its band gap is bigger than conventional photonic crystals,and the transmission band is more narrow.It provides a theoretical basis for the development of high quality low loss resonator,microwave antenna, transmission grating,optical waveguide devices.