A palladium-catalyzed carboxylic acid-directed cross-coupling of an ortho-C(sp(2)) atom of aromatic acids with aliphatic aziridines to construct the beta-arylethylamine skeleton via C-H activation has been developed. The reaction proceeded under mild conditions with great substrate scope. Meanwhile, the beta-arylethylamine skeleton in drugs or bioactive compounds could be easily generated in a single step. A catalytic amount of cesium carbonate was crucial to realizing the selective beta-arylethylamine synthesis.