A dispersion-compensating square-lattice photonic crystal fiber for broadband compensation which covers the S, C and L communication bands, i.e. wavelength ranging from 1 460 nm to 1 625 nm is proposed in this paper. Theoretically, it is shown a negative dispersion coefficient of about -595 ps/(nm·km) to -1 288 ps/(nm·km) over S to L bands and -975 ps/(nm·km) at the operating wavelength 1 550 nm. The relative dispersion slope is perfectly matched to that of conventional single-mode fiber of about 0.003 6 nm^-1. Besides the proposed photonic crystal fiber shows the large nonlinear coefficient of 61.88 W/km at the operating wavelength of 1 550 nm. Moreover, the variation of structural parameters is also studied and discussed here.