To validate flow fields on Multiphase separator, PIV(Particle Image Velocimetry) study was performed. The free water knock out(FWKO) vessel was designed by 3.178m3/day(20bbl/day) and SOR(Steam to Oil Ratio)=3.5 with Stokes law. In order to study for experiment, the feed condition of emulsion was Tin=80℃ and Pin= 1atm. To simulate bitumen emulsion, the working fluid was mixed Bunker fuel oil C and water(80℃). A FWKO vessel was adopted visualization window for flow visualization at internal baffle vicinity. The flow at internal 3rd baffle was visualized with 532nm wave length green laser(MGL-N-532A) and captured with CCD camera. The vector field was analysed by 4G insight code.