We investigate slow light properties of optical surface modes sustaining at the interface of two-dimensional photonic crystals and uniform medium (air). The manipulation of the structural parameters at the surface governs the modal field distribution of the surface state. The spectral and temporal behaviors of the slow mode are numerically explored by utilizing both plane-wave expansion and finite-difference time-domain methods. We show that the group index and bandwidth can be tuned within a wide range. The distortion free optical pulse propagation is supported by the presence of low group velocity dispersion behavior of the slow light surface mode photonic structure. (C) 2012 Optical Society of America