Abstract: Aiming at the odor source localization in a ventilated indoor environment, a simulated annealing based odor source localization algorithm for a single robot is proposed. Dominated by the flow field, the plume released from an odor source in the room is meandering and intermittent. Moreover, the local concentration maxima may appear in the eddy areas. In this paper, the odor source localization is regarded as a dynamic function optimization problem. The simulated annealing strategy is used to obtain the optimal solution of the concentration distribution function, namely the location of the odor source. The algorithm doesn't need the wind information, so the influence of the flow-field fluctuation is reduced. The relationship between odor concentration and odor-source distance is also studied, and an objective function for simulated annealing that is approximately linear with the odor source distance is presented. The experiments in an actual ventilated indoor environment show that the robot using the proposed method can trace the dynamic odor plume and eventually declare the odor source in an 8m×6m region, and the average localization time is about 10 min. In the search process, the robot is able to jump out of the local maxima effectively.