According to the characteristic of high temperature and high salinity and 80% of the horizontal wells completed with screen pipes in Zhongyuan oilfield， a heat resistance and salt tolerance system， composed of 5000 mg/L permeability regulator agent cationic ternary polymer RPM，6000 mg/L cross-linking agent PFR and 300 mg/L stabilizer JN，was developed，and the heat-resistance， salt-tolerance， thermo-stability and plugging property of the system were evaluated. The result showed that the heat resistance of the system was up to 90℃， the salt tolerance of the system was of 25 × 10⁴ mg/L（among which， Ca²⁺ and Mg²⁺ concentration was of 5000 mg/L）， the gel strength was above 5×10⁴ mPa·s and the thermo-stability was more than 90 days. The system had good selectivity and the water plugging efficiency reached up to 89% while the oil plugging rate was only 17%. The system could plug water in horizontal wells without oil well operation， especially suitable for water plugging in horizontal wells completed with slotted screen without packers and in open hole mode.