Abstract: Starting with the influence on the movement rules of small cavities,the mechanisms of emerging a single spherical bubble are study from the aspect of the turbulent coherent structure near the wall. A dynamic equation is established for the bubble and single spherical sand under the non-turbulent coherent structure near the wall,and then under the turbulent coherent structure near the wall. Through comparison,it can be seen that the turbulent coherent structure near the wall influences directly the cavitation of the bubble.