Abstract: The coalescence time between two contacting bubbles was measured experimentally in different acoustic pressures and frequencies using an imaging system with a high-speed video camera, and taken an analysis to the influence of secondary force and maximum oscillation velocity on the coalescence time of two contacting bubbles in this paper. It was found that under the action of different acoustic pressure and frequency, the coalescence time increase with secondary force and maximum oscillation velocity. Analyzed the influence of bubble coalescence time to compare secondary Bjerknes force and maximum oscillation velocity used the fitting formula shown that the secondary Bjerknes force are the critical factor to affect the bubble coalescence.