In this paper, the data acquisition system of PIV (Particle image velocimetry) system is investigated. Taken FPGA (Field programmable gate array) as the main controller, the acquisition, processing and transmission of particle images is completed, and communications between the designed system and computers are obtained. The interfaces between the system and CCD cameras follow the protocol of Camera Link, which controls CCD cameras, makes a signal transformation from LVDS to TTL, and accomplishes the serial communication between cameras and the system. The interfaces between the system and computer are based on networks, which solves the problem of distance control of the system. These functions were validated by experiments, in which the acquisition of images in PIV system is completed.