Abstract: In order to study the movements of char powders in laminar entrained flow reactor, a transparent experimental apparatus was designed for Particle Image Velocimetry(PIV) measurement of flow field. The velocities of char powders whose mesh size was between 100 to 120 were investigated by PIV at the different flow rates of 1.0-2.5 m3/h. The results indicated that the axial velocity of char powers in the pipe center was very small near the outlet, subsequently rapidly reached the maximum and then decreased. The axial velocity at the center of pipe reached a maximum in the region within 1.8-123.8 mm. The axial velocity distribution was a parabola-like curve along the radius. The relationship between Re and the dimensionless residential time of char powders was obtained finally.