The invention discloses a dynamic power flow control device based on a wide-range controllable transformer including bidirectional thyristors. The dynamic power flow control device is formed by a controllable transformer, a power unit, a measuring and controlling module, a cross phase conversion module, a filter capacitor, an input/output voltage transformer and an output current transformer. The dynamic power flow control method is carried out in a way that an electronic power switch which can be turned on/off quickly is employed to control the turn-on/off of a tap joint at the output side (secondary side) of the wide-range controllable transformer, other two phases of windings are connected in series with each phase tap joint of the wide-range controllable transformer, at the same time, four bidirectional thyristors are added to change the conducting direction of the cross phase winding, and therefore the phase and amplitude of the output voltage of the controllable transformer can be changed in a maximum range, and active power and reactive power can be adjusted; because the conduction of the tap joints of the wide-range controllable transformer is controlled, the dynamic power flow of a power network can be adjusted and controlled. The dynamic power flow control method for the wide-range controllable transformer including the bidirectional thyristors is characterized by being low in cost and high in dynamic power flow control reliability.