The polarization properties of photonic crystals containing single-negative materials were discussed by transfer matrix method,the results indicate that at the normal incidence,the transmission spectra of TE and TM modes are identical.With the increase of incident angle θ,the transmission spectra of the two modes move towards short-wave direction together with the forbidden band width increase,and the change of TE modes is greater than TM ones.The greater the incidence angle is,the more obvious this change will be.The bottoms of the quasi-forbidden band reduce gradually and the width is narrower slightly;the positions and width of forbidden band remain unchanged when number of period N increases.Whereas,the number of oscillation peaks M located at the top pass-band between the two bands will increase,and M and N obey the formulae M=N-1.The transmission spectra of TE and TM modes move towards long-wave direction together with the forbidden band width increasing.The same results can be observed when geometric thickness of the medium increases.The geometry thicknesses of the medium variation are same,the variation of the forbidden band width of the transmission spectrum of these two modes were also same,respectively.