It is confirmed through theoretical derivation that auto-correlation function of signal power waveform contains a pulse, whose location can be used to estimate chromatic dispersion. On this basis, the algorithm of chromatic dispersion monitoring is given. This method is verified in 112 Gb/s (28 GBaud) polarization division multiplexing non return to zero quadrature phase shift keying (PDM-NRZ-QPSK) experimental system. Using OptiSystem and Matlab, 56 Gb/s single polarization QPSK and 112 Gb/s PDM-QPSK simulation systems are setup and the applicability of this method to code pattern of NRZ, RZ67, RZ50 and RZ33 is analyzed. The experiment and simulation results are consistent with the analytical derivation, which confirms the feasibility of the method. The experimental monitoring error is less than 275 ps/nm, and the monitoring error of simulation is less than 185 ps/nm.