Abstract: The anomalous group velocity at band edge of photonic crystal can bc used to enhance some optical process，which has applications in optoelectronics field.In this paper，SOI material was taken for example，the structure parameters of photonic crystal operating at band edge were designed by 3D PWE method and the triangular lattice air-hole silicon photonic crystal was fabricated by the combination of EBL and ICP etching.The position of band edge was obtained by the measurement of transmission characteristics，there is a difference between the measured band edge and designed band edge，which is mainly due to the larger size of air holes than the designed value.The photonic crystal whose band edge lying at 1548nm was obtained by fabricating a series of photonic crystal structures with the same lattice constant and different air hole radius，this wavelength is basically in accord with the designed 1550nm.

Key words: photonic crystal slab, SOI, photonic bandgap, band edge, group velocity