The phase error of electronic transformer is an important factor which influences the measurement accuracy. However,the phase error can be modified through proper phase compensation scheme. This paper introduces the principle of the electronic transformer and analyses the causes of phase error. The phase compensation schemes, such as all-pass filter, phase-shifted algorithm of short data window, phase-shifted algorithm of Fourier are introduced. The influence of the harmonic is also researched. On this basis, the paper puts forward the improved schemes of phase compensation: sampling points removed and the linear phase of all-pass filter. The experiment shows that the phase error of transformer can meet the class 0.2 accuracy requirements and with feasibility.