Abstract: The investigations of the relative motion of bubble and particle currently conducted is predominately theoretical research with very few work being directed toward the aspect of experimental study. Following a description and analysis of the direct and indirect methods for observation of such a motion, an experimental apparatus capable of making the observation is developed based on the above mentioned two methods, and the apparatus developed is used for making a study of the relative motion of bubble and raw coal particle at Gongwusu Coal Preparation Plant, Inner Mongolia. Test result shows that: the coal particle assumes a free settling state when it moves to the area far off the bubble and then deviated from its original motion direction and finally tends to move along the bubble′s tangential direction when it comes nearer to the bubble; the velocity of motion of the particle is rather steady in the area away from the bubble, and then the velocity slows down with the reduction of the distance between the bubble and the particle, and finally comes down to the lowest value at the time when the particle collides with the bubble; after the collision, the particle starts to slide down from the bubble and moves faster and faster and reaches a highest value when it comes to the bubble′s equator position, and then it moves slower and slower and finally comes off the bubble when it moves to the position 0.34 mm below the bubble′s central line.