Instantaneous velocity distribution within coaxial circular pipe for measurement velocity of high speed is acquired simultaneously by applying the 2-dimensional PTV system consisting of a pulse generator(AOM:Acousto-Optical Modulator), a continuous-output laser and a PC image grabber together with experimental apparatus. The basic mechanism of AOM and vector identification method and performance-related image processing techniques are discussed. Representative measuring regions $90{ imes}90$mm are selected and instantaneous vectors are represented and fully developed turbulent flow of maximum velocity up to about 1.0 m/sec is obtained.