This invention relates to a dynamic distribution method and a device for channels in radio network, which sets up a standard picture to modelize the environment between access points and users in theradio network and then stipulates a limit rule for regions of nodes of all access ends and nodes of client ends and gets an approximately optimized solution for channels distributed dynamically by operating sum-product repeatedly to increase data transmission of radio network greatly. This invention further applies user mutex regions to guarantee the link quality between users and access points.