To investigate cavitation effect induced by Q-switched focused laser pulse underwater, the influence of initial radius of cavitation bubble and adiabatic exponent on kinetics of cavitation bubble has been analyzed theoretically. It indicates that the initial radius affects the radius of dynamic bubble. With the increase of initial radius, the bubble′s resonance period and the maximal radius will also increase. The maximal bubble radius increases with the increase of adiabatic exponent. Compared with initial bubble radius, the adiabatic exponent affects bubble dynamics less significantly. The bubble resonance periods have no significant difference under different adiabatic exponents. Cavitation bubbles can be induced by Q-switched Nd∶YAG laser pulse focused underwater. Dynamic cavitation bubbles and plasma are captured by high-speed photography. At the same time, the acoustic signal is detected by a hydrophone. The experiment result shows that the highest energy of bubbles and shock waves exists mainly in the first two oscillations. At the second and third maximum radius, the bubble energy reaches 31.9% and 9.96% of the highest bubble energy which happens at the first maximum radius respectively, and the energy of shock waves at the second and third collapse reaches 51% and 16.8% of the highest energy respectively. Subsequently, the energy of bubble and shock wave is attenuated dramatically.