Dispersion monitoring is a key technique of realizing high-speed optical communication. The structure can be integrated on a chip when using the nonlinear effects of optical waveguides to monitor dispersion. Silicon optical waveguides have notable nonlinearity with the nonlinear refractive index as 5×10-18 m2/W. When the signal and the pump light go through the silicon optical waveguide after being coupled,high nonlinear effects,such as self-phase modulation (SPM) and cross-phase modulation (XPM) will occur. These effects will induce changes in the spectrum of the optical signal. The different dispersions of the link lead to different extent effects of SPM and XPM. By effectively setting the central frequency and bandwidth of the filters,the different spectrum changes related to SPM and XPM can be detected simultaneously,so to monitor the link dispersion can be realized. The monitoring dispersion range reaches ±40 ps/nm.