This　article　investigates　the　nonlinear　dynamic　characteristics　and　stability　of　an　axial　flow　compressor　with　tip　clearance　and　ball　bearings.　The　compressor　rotor　system　is　modeled　with　the　aid　of　the　finite　element　technique　and　a　nonlinear　ball　bearing　model.　The　aerodynamic　destabilizing　forces,　i.e.,　the　Alford　forces,　induced　by　the　nonuniform　tip　clearance　when　the　rotor　is　whirling,　are　acquired　using　known　experimental　data　and　a　mathematic　model.　Simulation　results　show　that　the　Alford　forces　and　nonlinear　bearing　reactions　provoke　respectively　the　emergence　of　backward　and　forward　resonance　frequency　components,　and　induce　the　system　to　lose　stability.　The　experimental　results　are　perfectly　interpreted　by　the　proposed　analysis,　which　indicates　that　the　combined　effect　of　tip　clearance　and　ball　bearings　is　significant　on　the　dynamic　characteristics　and　stability　of　the　rotor　system.