Abstract: The topology of Ad Hoc networks using directional antennas is more complex than that with traditional omni-directional antennas. Based on a given steered beam directional antennas and using a method to obtain local neighbor location information, the authors propose a distributed topology control algorithm—SDTC(the steered beam directional antenna based topology control algorithm). The topology is controlled not only by adjusting the transmission powers of nodes but also by changing the direction, beam width and gain of directional antenna. Each node in the networks needs to take the responsibility of collecting information of its neighbor nodes, choosing the optimum adjacent nodes by using the strategy of power control scheduling, and then selecting the minimum transmission power as its transmission power, which can cover all of the optimum adjacent nodes it has chosen. The algorithm preserves the connectivity of the resulting topology, which can be transformed into the one equipped with bi-directional links as well. At the same time, the resulting network topology can reduce the energy consumption, decrease the traffic interference, and improve the network throughput as the results of less node transmission power and lower node degrees. Simulation results show that the proposed algorithm significantly improves the network performance. And the steered beam directional antenna based topology control algorithm for mobile Ad Hoc network remains to be studied in the future.