Disclosed is a method and apparatus for dynamic channel assignment (DCA) in a wireless network, which describes the complex channel assignment problem with a decoding problem. The invention describes the decoding problem with a normal graph and specifies all the local rules enforced by all the nodes at access point sides and subscriber sides. Then, the invention carries out the sum-product algorithm to solve the DCA. It is not only a fully-distributed low-complexity DCA technology, but also significantly increases the network throughput. The invention further adopts the concept of subscriber exclusive region to guarantee the link quality between a subscriber and an access point.