Abstract: For vibration is an important factor among all influencing factors of coal and gas bursts, gas adsorption experiments of coal were done and crack growth in coal was analyzed under vibration conditions. The mechanism of coal and gas bursts was discussed according to experimental and theoretical results. It is shown that under the action of vibration the gas content of coal and the adsorption ability decrease, and after vibration the time to reach the gas absorption equilibrium in coal and the adsorption equilibrium pressure increase, indicating that vibration makes free gas increase and the gas content of coal reduce. Vibration also leads to the increasing of crack number and crack growth rate, and when the vibration strength arrives at some value a large-scale connected crack network appears. The integrated influence of vibration on the coal and gas system increases the danger of coal and gas bursts.