In order to study the absorption effect of doping on the polarization wave of defect mode of positive-negative photonic crystal,the complex refractive index is introduced and the characteristic matrix method is used.Analysis shows that the extinction coefficients of doping have obvious influence on the defect mode of TE and TM wave.And the influence on TE wave is greater.When the extinction coefficient is certain,the two relatively big defect mode of TE wave decreases with the increase of incident angle,but all the defect mode of TM wave increases with the increase of incident angle.This phenomenon can be used to make multi channel photonic crystal filter.