One of the main failure modes of rolling bearings is to produce defects on raceway or surface of rolling body,forming fatigue pitting corrosion,which has a great impact on bearing performance.For deep groove ball bearings,a dynamic model with square defects in outer raceway was established to obtain the influence law of defects on load distribution,and a bearing time-varying stiffness model was established to analyze the influence law of defect size evolution and location on time-varying characteristics of bearing stiffness.The results show that the average stiffness of bearing is not affected when the defect is located in the non-bearing zone; when the defect is located in the bearing zone,the average stiffness of the bearing is negatively correlated with the defect length and depth; when the defect location changes from bottom to non-bearing zone,the average stiffness of bearing decreases first and then increases.