The utility model relates to a light communication technology field especially relates to a free space optical communication system, including free space optical communications equipment, WIFI treater and monitoring device, free space optical communications equipment pass through the WIFI treater with monitoring device connects to carry out the data interaction through WIFI treater and monitoring device, make monitoring device send feedback control signal to the light path adjustment of free space optical communications equipment, with the free space optical communications equipment of realizing the local terminal alignment with the light path of the free space optical communications equipment of distal end. The WIFI treater produces that WIFI network signal is stable not to receive space geographic restrictions, does not receive free space optical communications equipment spatial position's restriction, to the receiving and dispatching light path of free space optical communications equipment carry on intellectuality and automatic detect with the control, can in time aim at the light path, easy operation weak point consuming time, it is not high to have overcome the alignment precision that free space optical communication system exists among the prior art effectively, inefficiency, defect such as not portable.