At present, the major oil fields in the eastern part of China are in the stage of high-salinity exploitation. The problems of inefficient and ineffective circulation are very serious. The large amount of produced liquid treatment leads to a sharp increase in production and operation costs. The main technical indicators of the injected wastewater often fail to meet the industry requirements. The residual polymers, crude oil and suspended solid particles in the wastewater are bound to cause blockage and damage to the low-permeability areas of the reservoir. In order to clarify the limit of the reservoir permeability for wastewater injection and to construct improved methods for the adaptability of wastewater reservoirs, this paper intends to use physical chemistry, polymer chemistry and reservoir engineering as theoretical guidance, and employ technical means such as instrument detection, chemical analysis and physical simulation. Taking the injected wastewater and reservoir properties of the XSG oilfield as the research objects, it will conduct experimental research on the reservoir adaptability and improvement measures of wastewater injection in high-salinity oil fields. The results show that the oil content, suspended matter content and median particle size of the injected wastewater in the three under-injected wells are far beyond the industry water quality standards. Their retention and blockage in the pore spaces of the reservoir rock cores are the main reasons for the under-injection of water wells. The minimum reservoir permeability of well 1# after injecting wastewater is slightly 16910-3m2, well 3# are slightly 10310-3m2. The optimal mixing ratio of clear water can increase the Zeta potential value of suspended particles in the mixed water., the stability of the suspended matter particles enhances, the particle size of the suspended matter and the compatibility with the pore spaces of the rock cores improve, and the degree of reservoir blockage damage is reduced. From a technical and economic perspective, it is recommended that the ratio of wastewater to clear water for well 1# and well 3# is 4:6 and 6:4.