A measurement technique that can measure the concentration of the solid particles in liquid flow was developed.The measurement system consists of a color camera and three LCD displays.The solid particles were put at the bottom of a cylindrical mixing tank in which JetA1 oil was filled.Transient mixing of the solid particles was performed by rotating a propeller type agitator with three different rotation speed(500,600,700 r/min).Mixing state was visualized by the LCD displays and a color camcorder.The color intensity of the glass particles changes with their concentration.The color information was decoded into three principle colors R,G,and B so that,the calibration curve of color-to-concentration was performed using these information.A neural network was used for this calibration.The transient concentration field of the solid particles was quantitatively visualized. A measurement technique that can measure the concentration of the solid particles in liquid flow was developed. The measurement system consists of a color camera and three LCD displays. The solid particles were put at the bottom of a cylindrical mixing tank in which JetA1 oil was filled .Transient mixing of the solid particles was performed by rotating a propeller type agitator with three different rotation speed (500,600,700 r / min). Mixing state was visualized by the LCD displays and a color camcorder. The color intensity of the glass particles changes with their the color information was decoded into three principle colors R, G, and B so that, the calibration curve of color-to-concentration was performed using these information. A neural network was used for this calibration. transient concentration field of the solid particles was quantitatively visualized.