On a self-made super-high shear strain rate rheometer, the rheological characteristics and apparent viscosity curves of a high-speed bearing grease were obtained under different working conditions. A new grease rheological model suited to a shear strain rate range of 0—3.5×10~6s~(-1) was presented. The results showed that the shear stress increased linearly at first and then increased nonlinearly with the increase in shear strain rate up to 1.5×10~6s~(-1), and finally the shear stress decreased slightly with the successive increase in shear strain rate. The shear stress increased with a decreasing rolling speed and an increasing contact pressure. The apparent viscosity decreased rapidly with the increase of shear strain rate at beginning and could approach the viscosity of the base oil if the shear strain rate surpassed 1.5×10~6s~(-1). The fits between the test data and the predicted values by the new model were fairly good. On a self-made super-high shear strain rate rheometer, the rheological characteristics and apparent viscosity curves of a high-speed bearing grease were obtained under different working conditions. A new grease rheological model suited to a shear strain rate range of 0-3.5 × 10 ~ 6s ~ (-1) was presented. The results showed that the shear stress increased linearly at first and then increased nonlinearly with the increase in shear strain rate up to 1.5 × 10 ~ 6s -1, and finally the shear stress decreased slightly slightly with the successive increase in shear strain rate. the shear stress increased with a decreasing rolling speed and an increasing contact pressure. The apparent viscosity decreased rapidly with the increase of shear strain rate at beginning and could approach the viscosity of the base The fits between the test data and the predicted values ​​by the new model were fairly good.