Abstract: Organic molecules with fluorine usually possess unique physical, chemical, and biological properties, thus playing an important role in material science and pharmaceutical chemistry. Meanwhile, the functionalization of organic molecules via C−H activation has drawn a broad attention in recent years. Therefore, C−H fluorination for the synthesis of fluorine-containing molecules is a very important and challenging project in organic synthesis. Directing groups such as pyridine and amide have been utilized to facilitate C−H fluorinations. However, most of the directing groups are usually installed into the substrates before the fluorination and uninstalled after the fluorination, thus reducing the step economy of the reaction. Carboxylic group is ubiquitous in organic molecules and it can dramatically increase the step economy if it is employed as native directing group. Indeed, it has been utilized as directing group in C−H activations such as arylation, olefination, acetoxylation. Carboxylic group directed C−H fluorination remains a challenge. In this research, by using the carboxylic group as a directing group, after optimization of the reaction conditions including additive, solvent, fluorination reagent and ligand, we realized the Pd-catalyzed ortho-C(sp²)−H fluorination of benzoic acid, which affords the ortho-mono-fluorinated product in up to 13% isolated yield. A pyridone ligand with a nitro group at the C-5 position and an amide group at the C-3 position was found to be able to promote this transformation. We believe that these results will benefit future development of carboxylic group directed C−H fluorination.