Abstract: The sum rate maximization non-convex optimization problem was studied for coordinated multiple point multiple input single output (MISO) interference downlink system subject to per-base station power constraints. In order to solve efficiently the sum rate maximization optimization problem, the primal sum rate maximization optimization problem was firstly decomposed into the transmission power minimization optimization problem and the sum rate maximization optimization problem of single input single output interference channel by using the hierarchical optimization method. Then, the transmission power minimization optimization problem was solved by using the second order conic programming method. The sum rate maximization optimization problem was solved by using convex approximation method and geometric programming method. Finally, a novel monotonic coordinated multiple point beamforming algorithm was proposed by solving alternately the above two sub-problems. The convergence of the proposed algorithm was proven by using the monotonic boundary sequence theorem. The numerical simulation shows that the proposed algorithm converges to stable point with about four iterations and the achieved optimal performance is very close to the optimal performance of the exhaustive search algorithm.