The invention provides a convertible unified power flow controller. The convertible unified power flow controller comprises at least one parallel transformer, three current converters, at least two series transformers, at least a group of alternating current switches and three groups of direct current switches, wherein at least one side of each series transformer is connected with at least one group of bypass switches in parallel, alternating current sides of the three current converters are connected into an alternating current system after connected with the at least one parallel transformer through parallel side switches, the two current converters on the series side are respectively connected with at least one group of the series transformers, and then are connected with a power transmission line in series, and direct current sides of the three current converters are connected with one another through the direct current switches. By adopting the structure, multiple running modes can be achieved, unified power flow controller functions of a single circuit can still be achieved when a random current converter breaks down, and simultaneously the convertible unified power flow controller is small in occupied area and low in cost, and has good economical efficiency, flexibility and reliability.