The invention discloses an automatic soldering tin machine for terminals. The automatic soldering tin machine comprises a terminal array conveying mechanism, a first terminal taking and conveying mechanism, a first flux coating mechanism, a rotating conveying device, a soldering tin quantitative-supplying mechanism, a welding mechanism, a turnover mechanism, a punching mechanism, a second terminal taking and conveying mechanism, a second flux coating mechanism and an automatic sorting device. Through the flux coating mechanisms, the terminals are stained with flux before tin soldering, meanwhile, through the soldering tin quantitative-supplying mechanism, the quantity of soldering tins is effectively controlled, then good welding quality between the terminals and the soldering tins is guaranteed, and false soldering is prevented effectively. In addition, through the automatic sorting device, qualified and unqualified soldered products are automatically distinguished so as to guarantee the qualification rate in follow-up machining.