The invention provides a power sub module for a novel flexible direct current transmission current converter. An emitting electrode of a second fully-controlled semiconductor device unit is connected with a positive electrode of a first diode, while the collector electrode of the second fully-controlled semiconductor device unit is connected with a negative electrode of a second diode; an emitting electrode of a first fully-controlled semiconductor device unit is connected with the negative electrode of the first diode, while the collector electrode of the first fully-controlled semiconductor device unit is connected with a collector electrode of a fourth fully-controlled semiconductor device unit; and a collector electrode of a third fully-controlled semiconductor device unit is connected with the positive electrode of the second diode, while the emitting electrode of the third fully-controlled semiconductor device unit is connected with the emitting electrode of the fourth fully-controlled semiconductor device unit. Compared with the prior art, the power sub module for the novel flexible direct current transmission current converter provided by the invention is low in cost, simple in operation, and capable of effectively restraining the direct current fault current when a direct current transmission line of an overhead line is in malfunction.