Abstract: To investigate the flexural fatigue behavior of post-tensioned prestressed CFRP-reinforced concrete beams, simply supported beams with both prestressed and non-prestressed longitudinal reinforcement in the tension zone made entirely of CFRP bars were designed. One static test and three constant-amplitude fatigue tests were conducted. The upper fatigue load limits P_max were 0.5P_u, 0.6P_u, and 0.7P_u, with a lower limit Pmin of 0.1P_u, where P_u is the flexural capacity obtained from the static test. The test results show that the prestressed CFRP-reinforced concrete beams possess excellent fatigue performance. The specimens under P_max=0.5P_u and 0.6P_u survived over one million cycles. All failures were governed by concrete crushing in the compression zone, and neither the prestressed nor the non-prestressed CFRP bars experienced tensile fracture, indicating good deformability of the specimens. The maximum deflection, crack width, and longitudinal reinforcement strain increased with the fatigue load. For the specimen under P_max=0.7P_u, the maximum deflection reached approximately 40 mm and the maximum crack width was 0.9 mm. Under the same load level, the fatigue strains in the prestressed CFRP bars, non-prestressed CFRP bars, and steel reinforcement were up to 4.6, 2.8, and 1.8 times their corresponding static strains, respectively. A calculation method for the strain non-uniformity coefficient of CFRP longitudinal reinforcement was proposed, accounting for the influence of the number of fatigue cycles and the fatigue load level (0.5P_u-0.7P_u). Based on this coefficient, methods for predicting the maximum crack width and deflection of prestressed CFRP-reinforced concrete beams were further developed for Pmax ranging from 0.5P_u to 0.7P_u. The results indicate that the proposed methods can predict the maximum crack width and deflection with reasonable accuracy.