Abstract: In this paper, a new Dynamic Frequency Selection (DFS) algorithm is introduced in detail based on Distributed Coordination Function (DCF) mechanism. The DFS algorithm has defined a parameter of channel quality assessment. According to the condition of channel interference, DFS can optimize parameters and assign frequency recourses dynamically, and therefore improve the system capacity adaptively. The paper gives the disposition processing and parameters. Simulation results show that DFS can improve total throughput in a dense and non-uniform load WLAN system.