The reliable magnetization model of current transformer core is of importance for the study on residual flux and saturation of the core. In this work， a new magnetization model of current transformer core based on stack operating is presented. The magnetization characteristics of the core are summarized， the classification for the existing various magnetization curves is completed， and the category of curves is determined in accordance with the variation of magnetic field intensity H and stack operating. Corresponding to various categories of B/H curves， the systematic expressions of calculating magnetic flux density B are given. The comparison between the B values calculated with the present model and the experiments verifies the accuracy of the present model.