Steam generator tube, which is commonly made of Inconel 690 alloy, is suffered from flow-induced vibration and worked under high-temperature and high-pressure water/steam environment. This working condition leads to significant synergistic damage of fretting wear and corrosion. Thus, to investigate the synergistic damage mechanism, a flow-induced vibration wear simulated method was used to investigate the flow-induced vibration wear behavior of 690 alloy tube against 304 SS plate at 100 °C, 200 °C, and 285 °C in steam/water environment. Results show that the fretting wear damage decreased with temperature in water environment. But for the steam environment, fretting wear damage decreased to a minimum value at 200 °C and then increased to a maximum value at 285 °C. The synergistic damage mechanism between wear and corrosion was analyzed. Wear can damage the material surface and promote oxidation. On the other hand, the oxide layer formed on the surface can protect the surface from wear or promote wear damage, which depends on its characteristics influenced by the environment.