Abstract: In physics, "source" refers to the starting point of matter or energy, while "sink" refers to the point of arrival of matter or energy. Underground explosions are equivalent to a simple energy source, whose energy radiates outward from the boundaries of each explosion zone in the form of radial force work, and the range of the damage zone determines the magnitude of the energy flow density of the radiated seismic waves. The elastic characteristic energy radiated from underground confined explosion and contact explosion was analyzed, and the energy factors corresponding to each zone of underground confined explosions were calculated. It is suggested that the characteristic energy factors can characterize the energy source characteristics of the "expansion center" of underground explosions very well. Compared with underground explosions, a detailed analysis was conducted on the energy balance relationship and adjustment mechanism in the ideal fluid cavity annihilation problem, and the relationship between work done by water pressure and energy accumulation, transmission and conversion were established. The characteristic energy factor was introduced to describe the characteristics of energy sink, which will provide theoretical reference for subsequent research on energy sink in solid materials.