In response to the problem of water channeling in the connected well group of the Halahatang Oilfield, based on single well rock thin section analysis, physical modeling, and mathematical modeling, the water flooding type of the closed fixed volume well group in the fracture development area is identified as the dominant channel water channeling type. In order to improve the development effect of high water content connected well groups, a heat resistance and salt -plugging agent has been formed on the basis of technical research, with a temperature resistance up to 140 ℃ and a salt resistance of 2.1 × 105 mg /L, through indoor evaluation of the system 's gelling property, temperature resistance, salt resistance, variable temperature viscosity performance, plugging property evaluation, pressure breakthrough performance, and oil displacement performance, all showed excellent performance. This system has cumulatively implemented 5 well groups in the connected well groups of Halahatang Oilfield, with 3 effectives well groups and an effective rate of 60%. The daily oil increase is over 5 tons. According to on-site statistics, the effective period of the plugging agent is about 160 days, providing a new technical reserve for the high water cut period of the ultra-deep, high temperature, and high salinity carbonate rock connected well group.