Abstract: Under different parameter conditions, the fretting fatigue test was carried out on self-designed bending fretting fatigue device with CuMg0.4 alloy used in hanging strings. The S-N curve was built up, and the damage area was analyzed according to a series of microscopic analysis equipment, such as three-dimensional morphometer, scanning electron microscope (SEM), electron microprobe (EPMA), etc. Then the bending fretting fatigue characteristics and damage related laws of the material were discussed. The results show that when the contact area is under elastic condition. The curve of bending fretting fatigue S-N shows the characteristic of " Z”. With the increase of bending load, the fretting fatigue life of the material decrease and then increases. In turn, it runs in part of the slip regime(PSR), mixed regime (MFR)and complete slip regime(SR). The contact area includes 4 forms damage mechanism, it’s abrasive wear, oxidation wear, fatigue wear and adhesive wear. The fretting fatigue crack propagation can be divided into 3 stages, from contact stress contral to bending fatigue stress contral.