There was a new down-hole BOP that was designed to control blowout effectively in exploiting petroleum gas. The BOP was a new blowout preventer with a good development prospect which can not only automatically shut underground, but also control and automatically discharge shut up-hole state on the ground. Through introducing structure and working principle of the BOP, as well as the finite element analysis of some key components, there has been showed that the down-hole blowout preventer met the strength requirements and had relatively high security. The down-hole blowout preventer with a simple structure can not only work reliably but also complete the act of preventing blowout and unlocking many times to prevent blowout effectively and to improve drilling operations safety and efficiency. It will have a bright development prospect.