A direct and regiocontrolled thiolation method to access β-amino sulfides through the palladium-catalyzed C(sp2)–H functionalization of stable enamines was described. The reaction was realized under mild conditions by adding an external phosphine ligand to prevent poisoning of the palladium catalyst by the sulfuric reagents. A possible mechanism was proposed according to the obtained results. The DFT calculation results were consistent with the experiment data, which gave the E isomers of the β-amino sulfides. The reaction was also performed on a gram scale and shows potential application in organic synthesis.