The flexural fatigue responses of HPFRCs using a simplified model were performed in this paper. The flexural specimens were tested under three-point bending test (3PBT) configuration using a specimen size of 40 × 40 × 160 mm³ with its span length of 120 mm. Two different types of reinforcing steel fibers were investigated in this study, including long-hooked and short-straight smooth steel fibers. The volume contents of the fibers were 0.0%, 0.5%, 1.0%, and 1.5%. Based on the experimental results reported in the previous study, the flexural fatigue responses of the HPFRCs were mathematically built using a simplified model by means of regression analysis with its least-squares technique. The simplified fatigue response curves of the HPFRCs were then evaluated and discussed.