The invention relates to a 
thyristor single-phase 
voltage adjusting circuit and a control method thereof. The 
thyristor single-phase 
voltage adjusting circuit is characterized in that the arrangement of a 
transformer, a 
rectifier bridge and the like is omitted, and an 
alternating current bidirectional zero-crossing 
signal is directly detected by a photoelectric coupler, so the stability and accuracy of the 
voltage adjusting circuit are improved; deviation positive and negative signals required by a 
control algorithm are detected by an effective hardware circuit, and can be sent into a main controller in a digital way, so as to omit the conversion time of an 
analog to digital converter; the 
control algorithm adopts the phase-shift triggering, the movement direction of a triggering angle is directly determined according to the deviation positive and negative signals, and the 
control algorithm belongs to the closed-loop droop control; a 
thyristor triggering circuit of the voltage adjusting circuit can generate a strong triggering wide pulse 
signal, so as to guarantee the stable triggering of a thyristor. The voltage adjusting circuit and the control method have the advantages that the cost of hardware is greatly reduced, and the time is saved; the real-time property, accuracy and stability of the 
control system are improved, and the cost of the whole circuit is reduced.