Abstract: This paper studies the problem of resource allocation for OFDMA systems. The problem is formulated as a weighted sum rate maximization problem subject to total transmission power constraints. A distributed resource allocation algorithm based on dual decomposition is proposed. The problem is decoupled into a master problem with regard to the base station and several subproblems with regard to the users. Each user can obtain its own subcarriers and power allocation scheme by solving the subproblem. The base station can make sure all the constraints are met and the weighted sum rate of each user is maximized by solving the master problem. Through decomposition, a complicated optimal problem is seperated into several independent subproblems that can be solved parallelly, so both the computational complexity and the caculation payload of the base station are effectively reduced. Simulation results show that the proposed algorithm can converge quickly to an approximated optimal solution in a small number of interations.