The Goos-Hnchen (GH) shift is investigated for a Gaussian beam reflected by a two-dimensional photonic crystal using the transfer matrix method. With frequencies in stop band,the GH shift is small for a perfect photonic crystal,while it is several times of lattice constant for photonic crystal with adjusted radius of air hole in surfaced layer. The property is helpful to improve the coupling efficiencies between photonic crystals and other micro-/nano-optical devices.