Abstract: To address the challenge of scaling due to hypersalinity in high-temperature geothermal water injection wells in the central and southern Hebei of Huabei Oilfield, which restricts the resource development, a high-efficiency high-temperature resistant scale inhibitor was prepared. Based on the analysis of on-site extracted liquid, such scale inhibitors as organic polyphosphates, quaternary ammonium salts, amino polymers, phosphorus-free polymers, and natural polymers were selected as raw materials to conduct indoor experiments on scale inhibition of calcium carbonate/calcium sulfate and formula optimization. The laboratory findings demonstrate that the optimal composite formula, at 110 ℃, is determined as follow: component A (m_EDTMP∶m_PESA=1∶5) and component B (m_ATMP∶m_HEDP∶m_PASP=1∶1∶3.5) are formulated at a mass ratio of 4:3, achieving a scale inhibition rate of 96.4%. This inhibitor works by mechanism of chelation solubilization, lattice distortion, and dispersion. The application in Ze 90 # heat exchange system exhibits the scale inhibition rate over 82.5%. The formula system of high-temperature scale inhibitor presents excellent stability and dispersion effects, providing technical support for the sustainable development of geothermal resources with hypersalinity.