The numerical model of underwater explosion bubble coupling with free surface is created based on boundary integral method and the corresponding program is exploited to get the calculated result which presents satisfactory precision with experiment data. From the basic phenomenon of the interaction between bubble and free surface, the dynamic behavior of bubble near free surface is studied systematically employing the exploited program including the ring rebound of bubble near free surface and spike of free surface as well as the relation between distance parameter buoyancy parameter strength parameter and Bjerknes effect near free surface to summarize relative laws that the dynamic behavior near free surface has close relation with these characteristic parameters. In the process of study, scope of applicability of Blake rule on the basis of Kelvin_impulse theory is discussed and the reason for inactivation of Blake rule is interpreted to present references to research on dynamic behavior of underwater explosion bubble near free surface.