In order to achieve the efficient regulation of the rheological properties of ultra-high performance concrete (UHPC), bentonite was used as an auxiliary cementing material and the performances of the prepared UHPC were evaluated. The fluidity, static yield stress, dynamic yield stress, plastic viscosity and thixotropy of UHPC slurry were studied, and the effect of different bentonite content on the rheological properties of UHPC slurry was systematically analyzed. The results show that: the overall fluidity of UHPC slurry shows a downward trend, and the decline amplitude gradually increases with the increase of bentonite content. When the content of bentonite increases from 0% to 15.0% (mass fraction), the static yield stress, dynamic yield stress and plastic viscosity of UHPC slurry increase significantly, by about 17.05 times, 5.78 times and 1.16 times, respectively. The hysteresis loop area and thixotropy index increase with the increase of bentonite content, and the thixotropy is significantly improved. Meanwhile, UHPC with bentonite still meets the advanced mechanical properties of UHPC.