Gas injection protection device

The utility model provides a gas injection protection device, include: the casing, the first end of casing is used for being connected with oil production pipe's upper portion oil pipe, and the secondof casing end is used for being connected with oil production pipe's lower part oil pipe, has the through -hole in the casing, and the through -hole is held by the second that the first end of casingextended to the casing, the slide bar, the slide bar is movably to be worn to establish in the through -hole, plugging assembly, plugging assembly's at least part sets up on the slide bar to cut offthe through -hole or make the through -hole switch on under the drive of slide bar, wherein, be provided with the ooff valve that is used for making upper portion oil pipe and the sleeve pipe intercommunication of oil well on the oil pipe of upper portion, during steam injection, plugging assembly makes the through -hole wall when adopting the oil pipe post in, and upper portion tubular column messenger ooff valve is opened