In present research,a 4×10Gbit/s wavelength division multiplexing (WD M) system is designed by theoretical simulation calculations to investigate the dispersion compensation.The dispersion of the system is compensated by chirp fi ber Bragg gratings (CFBG).The properties of systems are investigated with the n on return to zero (NRZ) and return to zero (RZ),respectively.The system is opt imized by the analysis of Q factor and eye diagram obtai ned by theoretical simul ations,and the best parameters are suggested to achieve the best performance of the system.The analysis indicates that the CFBGs can compensate different wave length signal′s dispersion accurately,and the systems show excellent performan ce.the best Q value of NRZ is calculated to be 17.80,and that of RZ is c alculated to be 52.55,respectively.