Slow light in square-lattice chalcogenide photoniccrystal (PC) holey fibers with uniform longitude geometry are proposed and theoretically investigated. By using the planewaveexpansion method, a largest normalized complete 2-D photonic bandgap (CPBG) width of about 7.4 is found in an optimized connected-rod square-lattice chalcogenide PC, and the CPBG remains open with a refractive-index contrast as low as 2.48:1. We then consider the PCs as cladding layers to form holey fibers, and group indices up to several hundreds are predicted.-Slow light in square-lattice chalcogenide photoniccrystal (PC) holey fibers with uniform longitude geometry are proposed and theoretically investigated. By using the planewaveexpansion method, a largest normalized complete 2-D photonic bandgap (CPBG) width of about 7.4　is found in an optimized connected-rod square-lattice chalcogenide PC, and the CPBG remains open with a refractive-index contrast as low as 2.48:1. We then consider the PCs as cladding layers to form holey fibers, and group indices up to several hundreds are predicted.