Flow-accelerated corrosion (FAC) is a piping degradation mechanism resulting in the loss of material from the inside of the piping that subsequently thins the wall. The FAC that causes costly plant repairs and personal injuries is generally accelerated by the single-phase fluid or two-phase mixture, which seems to be a very serious problem found in most of the power plants these days. Based on the measured data of pipe thickness, FAC phenomenon strongly depends on the piping layout and local flow conditions. A three-dimensional two-phase model is proposed with the aim of simulating two-phase behaviors found in the pipe and investigating the impact of these local parameters on FAC damage. Through three-dimensional calculation, liquid droplet impingement was found to dominate the FAC damage occurring in high-steam-quality flow. A simplified parameter is proposed to express an indicator of this normal impingement force. The magnitude of this parameter can represent the severity location of the FAC damage. Compared with plant-measured data of the wear rate, the predicted locations of serious FAC are in good agreement qualitatively. In addition, the phenomenon that different piping layouts will induce different FAC locations can be accurately captured in the current mode.