Based on the 2D triangular rods photonic crystal two-defect coupled-cavity waveguides, the new structure of slow-light waveguide is designed with better characteristics. The slow-light characteristic is simulated analyzed using plane wave expansion method. It is found that the mode outside the band will move into the band to form a guide mode by adjusting the radius of the defect rods. The waveguide structure with group velocity 0.0055c is obtained and the bandwidth is 135 GHz when c is the light velocity in vacuum. When the group velocity is about 0.01c, the bandwidth of up to 260 GHz is about to meet the needs of practical application. In addition, the waveguide structure is simple and tunable, and it can be applied to optical delay lines, all-optical buffer and other slow light devise.