Abstract: This paper describes that in atmosphere friction torque ofC7046112 bearings varied with axial load,rotational speeds,ball numberand lubricant.The test results showed that relations between bearingsaxial load and friction torque are not monotone increasing function.Theyare periodic function with maximam value and minimum value.Test re-sults are discussed also.The DZS—1 preload dynamic characteristic air-floating test equipmentis also introduced in this paper.