A transformer failure analysis system using a programmable chip in conjunction with a shock response spectrum analysis method to distinguish inrush current and fault current of a transformer and to monitor the phase of an AC power source inputting to the transformer by a phase detector. When an inrush current occurs, the programmable chip provides a control signal to delay the phase of the AC power source being inputted into the transformer, thereby suppressing the occurrence of the inrush current. When a fault current occurs, the control signal cuts off the AC power source from the transformer until the operator has tested the whole circuit architecture to debug and correct circuit application and eliminated the internal fault.