A large-scale and high-precision Chromatic Dispersion（CD） monitoring technique for high-speed coherent optical communication system is proposed

which combines the signal power waveform with amplitude and phase histograms characteristics. We conduct a simulation for 112 Gbit/s（28 GBaud） Polarization Division Multiplexing Quadrature Phase Shift Keying（PDM-QPSK） coherent optical communication system. In the simulation

the feasibility of this method is proved and the monitoring error is further analyzed. The maximum absolute estimation error of 62.1 ps/nm and the average relative error of 0.002 7 are achieved in the range of 6.4 to 48.0 ns/nm.