Dynamic tracking of laser spot is a key process in the establishment of free space optical communication. In this paper, a dynamic tracking system was presented. In this system, a two-dimensional (2D) galvanometer was used to change the angle of the optical axis of the incident beam at a certain scanning frequency as optical signal jitter simulator, and another galvanometer was used to track the jitter with quadrant detector (QD) and data processing module to acquire the position information of laser spot. Results indicated that the tracking accuracy of this system mainly composed of 2D galvanometer was as high as 27.8 μrad, and its linear deviation was less than 0.013. The system could still keep the dynamic tracking of the spot stable when the jitter frequency of the optical signal was less than 1000 Hz. Those results suggested that this system could be suitable for the short distance in free space communication due to its simple structure, easy to control and low cost compared with conventional system.