Since inrush current has the steeple wave with intermittent angle and the faulted current is based on the sine wave, there are different values of current power entropy. To fully use this characteristic, the information entropy to identify the inrush current of transformers is proposed. Transformer current experiences discrete sampling and differential filtering successively in the method. Starting current is set to compute entropy of current power. And then the adaptive threshold is used to identify inrush current. The simulation results demonstrate the method not only effectively identifies inrush current and faulted current, but also identifies the degree of current saturation.