The vibration characteristics of a single stage compressor test rig were studied and analyzed through aerodynamic characteristics testing. The results shown that the change of back pressure led to the rub-impact between blade and casing, and the low frequency and high amplitude vibration also occurred. Moreover, the main factors of blade rubimpact were investigated, and some improvements were given to avoid the blade rubimpact. The results in this paper provide the reference to the safe operation of axial flow compressor test in investigating the aerodynamic characteristics.