To overcome the shortcomings of existing delay compensation of the electronic transformer，a dynamic phase compensation algorithm of sampled value is proposed.First，the process of phase difference generation is explained.Then，a method of real-time calculating and dynamic correcting the phase difference within the merging unit is presented according to the uncertainty of delayed displacement.Coordinate rotation digital computer（CORDIC）based plane coordinate rotation and square root calculation are dealt with.Meanwhile the corresponding pipeline structure in field programmable gate array（FPGA）is optimized，improving the algorithm speed and reducing additional delay.Simulation and experiment results through the electronic transformer calibration system have verified the proposed method is able to improve and enhance the phase accuracy of the electronic measuring transformer.