Abstract: With continuous development of oil fields, many injection wells have been injected for a long time. Due to various reasons, the sealing between the top packer and sealing or the top packer with casing is not closed. Even more, the cementing quality of the casing external wall became poor gradually, and cracks occurred due to casing corrosion and deformation, causing annulus pressure, resulting in wellhead casing annulus pressure and well control risks of wellhead. Through cooperative research and development of APS wellhead protector, K344-SJ210 hydraulic control expansion self-locking pressure processor, the pressure can be isolated effectively in the well, with no wellhead pressure, which can effectively ensure the safety of the wellhead.