Abstract: The casing of offshore low-permeability tight sandstone fractured wells mainly has an outer diameter of 177.8 mm and 244.5 mm. The formation temperature and pressure are high, and the number of injection cycles is large. Conventional Y441 packers are used in combination with hydraulic anchors for fracturing operations. The pressure in the annulus below the packer can be converted into an upward unseating force on the packer. There is a risk of the packer being unseated when the pressure difference between the tubing and the annulus is low or when the hydraulic anchor slips. A double slips anti-unseating structure was designed for the fracturing packer. Numerical and physical simulations were carried out in the set state and during the annulus pressurization process to verify its anti-unseating performance. The API-11D1-V3 test was also conducted at a maximum temperature of 150 ℃, and the feasibility of fracturing without a hydraulic anchor was analyzed. The field application results show that the double slips anti-unseating packer can be used for multiple cycles of single-layer or multi-layer fracturing operations in casings with an outer diameter of 244.5 mm. It is suitable for fracturing wells with a wellhead operating pressure not exceeding 50 MPa and a reservoir temperature not exceeding 150 ℃. The hydraulic anchor can be omitted by adding an expansion joint above the packer or applying a certain tonnage of downward pressure. The research on the double slips anti-unseating packer provides a new technical direction for the design of offshore fracturing tubing strings and offers reference experience for the development of fracturing packer tools.