The invention provides a current conversion apparatus of an electrified railway ground surface flexibility automatic passing over of neutral section system. The current conversion apparatus comprisesan -phase side single-phase multi-winding rectifying transformer T1, a -phase side single-phase multi-winding rectifying transformer T2, an inversion transformer T3 and a three-port four-quadrant current converter BLQ; the three-port four-quadrant current converter BLQ performs alternating current-direct current-alternating current conversion on the accessed -phase and -phase traction bus power supplies, then outputs a path of single-phase power supply through a high-voltage winding of the inversion transformer T3, then is connected with the secondary-side high voltage of the -phase and -phase side single-phase multi-winding rectifying transformers in series, and then performs voltage synthesis to supply power for an electric split-phase neutral section N of a contact network. By taking the advanced power electronic current conversion apparatus and special transformers as the core components, continuous power supply for the electric split-phase neutral section of the contact network can be realized, so that a train can perform passing over of neutral section without power down, and electric arc, overvoltage, overcurrent impact and the like arenot generated.