In oil and gas exploration and development operations，the geological conditions are complex，and the salinity of formation water in salt-gypsum layers is extremely high. A large number of metal cations have a serious negative impact on the viscosity and filtration reduction of water-based drilling fluids. In order to solve this problem，an anti-multivalent cation zwitterionic hyperbranched polymer filtrate reducer XZ-DJ2 was prepared by introducing a branching agent on the basis of zwitterionic polymer. The optimum reaction conditions were explored through experiments，and a series of characterization tests on its physical and chemical properties were carried out. The rheology，filtration loss reduction，salt resistance，particle size and Zeta potential of the drilling fluid base slurry after adding XZ-DJ2 were tested. The results showed that after adding 2% XZ-DJ2 into the base slurry，the Zeta potential changed from ?31.9 mV to ?42.4 mV，and the absolute value of Zeta potential increased，indicating that XZ-DJ2 could improve the stability of the system. The filtration loss before and after aging at the temperature of 150 ℃ for 16 h was 5.6 mL and 6 mL，respectively，which was significantly lower than that of the base slurry without XZ-DJ2，being of 26.6 mL and 31.8 mL，respectively，indicating that XZ-DJ2 had good filtration loss reduction performance. With the increase of XZ-DJ2 dosage，the viscosity of drilling fluid increased and the filtration loss decreased slightly. After contaminated by 30% NaCl、30% KCl、5% CaCl₂、5% MgCl₂ and 1% Al₂（SO₄）₃·18H₂O，the viscosity of the drilling fluid was significantly reduced，but the filtration loss change little，being of 6.3，6.2，5.2，6.8，7.0 mL，respectively，indicating that XZ-DJ2 had excellent temperature resistance and multivalent cation pollution resistance，and XZ-DJ2 achieved the fluid loss reduction effect by improving the compactness of the filter cake rather than improving the viscosity of the drilling fluid，which is conducive to drilling speed and further save drilling fluid operating costs.