By using image difference and gray stretch technique
image histogram analysis method was used to investigate the movement of particles in image sequence. The result shows that the movement of particles has close relation with the dispersivity of pixels' greyvalue. The number of pixels with high brightness indicates the fierceness of particles. The brightness of pixels with similar grayscale will decrease with the slowdown of particles. After eliminating the influence of noise and taking consider of the gray level of pixels within certain range
a weight factor based on logarithm function was introduced to evaluate the intensity of particles' movement. Application of this algorithm in image sequence of fluidized bubble verifies the validity of this method.