In the decade of information, with the increment of the data rate and capacity in communication, free space optical
communication (FSO) has been paid much attention by many countries since it integrates the advantages of fiber
communication and other traditional wireless communication technologies, such as large capacity, low cost, convenient
deployment and flexibility. This paper concerns with the research on the signal tracking technology of FSO. Considering
that suppressing vibration is a difficulty of FSO, so suppressing methods are discussed in the paper. As a base, the ATP
(Acquisition, Tracking, Pointing) technology of FSO communication system is analyzed in this paper. And a new signal
tracking system for FSO communication is described. The main structure, integral parts and detailed work process of this
signal tracking system are introduced in detail.