To realize the active light control with compact structure, we design an optical switch based on plasmonic demultiplexer. The device is composed of metal-Kerr nonlinear material-metal waveguide and resonant cavities, providing the function of active optical regulation. With the multiple parameter optimization, the signal with wavelength of 1310 nm can be controlled by pump light with wavelength of 735 nm. The signal can realize output and cut off at two output. The directional extinction ratio can reach to 29.4 dB and the response time is only 50 fs. The dual-channel all-optical switch has the advantages of simple and compact structure, easy integration, fast response, and so on, it will has importance application in naono-integrated optics.