AbstractThe TiO2 nanocomposite photocatalyst P25/fluorinated graphene (P25/FG) was synthesized using the one‐step hydrothermal method. During hydrothermal process, the partial defluorination of FG, the surface fluorine doping of P25 as well as the deposition of P25 on graphene nanosheet were achieved. The P25/FG photocatalyst behaved excellent photocatalytic activity in photodegradation of methyl orange (MO) with degradation rate constant of 0.169 min−1, 5.6 times of that for P25 and 2.2 times for P25‐graphene catalyst under same conditions. It was demonstrated that the enhancement of photocatalytic activity of P25/FG can be attributed to the multiple modification of P25 brought by FG, including the effect of fluorine‐doped graphene, surface fluorine doping of P25 as well as dissociative fluorine ions in solution generated from UV‐assisted photocatalytic defluorination.