The line defect waveguide structure of triangular lattice photonic crystal with air ring is studied. The influence of scatter inner radius R_in and outer radius R_out on the slow light properties is studied. These results indicate that the ratio of R_in/R_out in 0.15~0.35 is favorite to obtain the broadband slow light. The outer radius R_fout of the air ring rows next to the waveguide channel has the more impact on the properties than the inner radius R_fin of the air ring rows next to the waveguide channel. The air holes scattering element on both sides of the waveguide are benefit to reduce the group velocity, while the air rings are helpful to get wider slow light bandwidth. However, the ideal slow light phenomenon is obtained in the asymmetric line defect waveguide which is combined air holes with air rings. The group velocity 0.0086 c which has low dispersion is obtained with the wavelength range of 6.588 nm.