Abstract: In the article, three mechanical conditions in the theory of "spherical shell instability stability" occurred in the coal and gas outburst are used to analyze loose blasting mechanism in the prevention and control of coal and gas outburst, namely through the use of loose blasting technology to make three mechanical conditions that all meeting in the coal and gas outburst become only one condition, so that the liberation of coal lost the outburst risks. The thickness of safety coal pillar, gas pressure and stress schematic before and after the loose blasting are established on the base of the dynamic stress field model in the coal and gas outburst, and the feasibility, advantages and measures on the loose blasting technology in the prevention and treatment of coal and gas outburst are drawn. Finally, some of the recommendations are advanced to improve the safety of loose blasting.