Objective: To study the testing repeation and inf'luential factors in the blood viscosity testing with the cone and plate viscometers. Methods f Blood viscosities of SD rat and hamster were tested in different temperatures and shear rates. Results f When the shear rates were in 11.25～45s, the blood viscosities come down quickly with the increase of the shear rate, when the shear rates were higher then 150s , two of the testing values tended to be constant; When the temperatures were below 37℃, the blood viscosity of the hamster in high shear(225s ') and low shear (11.25s-1) went up with the temperatues fell, When the temperature were higher than 43oC two kinds of blood viscosity went up with the increase of temperature. When the temperatures were in 37-43℃, the changes of the blood viscosity with the temperatures were less, The changes of the plasma viscosity was negatively related to that of the temperatures (r=-0.96, p＜0.01); Some other factors such as erythrocyte sedimentation in the testing couse were also affect testing values. Conclusion: The testing values teasted by the cone and plate viscometers were affected by manifold factors.