The invention discloses single-phase power supply devices, a novel electric railway tractive power supply system comprising the single-phase power supply devices and a control method. The power supply system comprises a power supply synchronous controller, a plurality of the single-phase power supply devices and a plurality of interval interconnection switches; each single-phase power supply comprises multiple secondary line winding transformers, a plurality of power conversion units and a master controller; the power supply synchronous controller is responsible for controlling effective values, frequency and phases of voltage of the whole traction network to be consistent, the single-phase power supply devices are used for converting a three-phase power supply into a synchronous single-phase power supply according to a synchronization instruction, and the interval interconnection switches are connected with all power supply intervals to form a unified whole. According to the invention, the problem about electric energy quality of a public supply network due to a traditional tractive power supply system is effectively solved, the controllable, reliable and continuous power supply is provided for an electric locomotive, meanwhile, an ice melting function is realized, and safety and reliability of the tractive power supply system are guaranteed.