Abstract: Accurate underwater acoustic positioning is a prerequisite for conducting ocean resource exploration, submarine pipeline laying, ocean topographic mapping, and other ocean development activities. Among them, a typical target for positioning is a fixed beacon that can transmit periodic acoustic signals. In this paper, a single autonomous underwater vehicle (AUV) is used to locate such targets. One of the key issues is the AUV's route planning. Traditional route planning methods usually focus on obstacle avoidance and path length optimization, without considering the specificity of the positioning problem, while the final positioning accuracy is closely related to the route. Therefore, the traditional route planning method is easy to lead to poor positioning accuracy of the planned route. In view of this problem, this article first introduces the Bresenham circle drawing algorithm to plan a circular route on the basis of traditional ant colony algorithm for keeping the positioning target within the AUV side-sonar view and avoiding signal loss. At the same time, a positioning accuracy factor is added to the pheromone design, so that the planned route can fully consider the positioning accuracy. Simulation experiments show that the method proposed in this article can balance the positioning task with traditional route planning obstacle avoidance ability and path length optimization ability, and improve the positioning accuracy and robustness for acoustic beacon targets.