Abstract: High temperature rheological properties of drilling fluid have important influences on fast and safe drilling in deep or ultra-deep wells. Rheological properties of drilling fluid after high temperature aging and cooling do not represent the rheological properties at high temperature conditions. High temperature rheological properties of water-based temperature resistance drilling fluid system were studied with the Model 50SL high-temperature high-pressure rheometer, so the rheological parameters were obtained, and the maximum experimental temperature reached 220℃. The effects of temperature, density, polyalcohol, polymer and salt on rheological properties of drilling fluid were studied. The results show that plastic viscosity and temperature complies with the relation of quadratic function. Plastic viscosity decreases exponentially with increasing temperature, and the higher the density, the greater influence by temperature. In lowtemperature range(less than 150℃), polyol and polymer have obvious influence on rheological properties of drilling fluid system, and less influence in high temperature range (150-220℃). Salt has more obvious influence on rheological properties of high density drilling fluid system. The study provides guidance for regulating rheological properties of drilling fluid system in field operation.