Abstract: To design and realize a large scale video frequency switching network, which is rearrangeable and nonblocking, taking the video crosspoint switch as the basic switching unit, a three stage nonblocking Clos network was constructed, and the signal route was selected by a route table. The multi channel analog video signals can be transmitted simultaneously without blocking by rearranging the signal route. Comparing with the traditional single stage video switching network, the number of crosspoints and switching units used in the three stage network is reduced substantially and the whole switching system is simplified greatly; because signal line is not connected each other, the crosstalk between video signals is reduced and the transmitting performance of video switching network is improved distinctly.