After analyzing the characteristic of core magnetic flux of CT during CT saturation, a new method based on dynamic virtual magnetic flux to identify CT saturation is proposed. The method calculates the dynamic virtual magnetic flux with secondary current with the relations between secondary current and magnetic flux. The method can identify CT saturation with the characteristic of core magnetic flux that the time between the starting of CT saturation when the magnetic flux reaches the maximum and zero time of secondary current is shorter, and identify linear data with that value of core magnetic flux during linear data is less than it during CT saturation. The method uses the characteristic of core magnetic flux to identify CT saturation, which will not affected by the characteristic of secondary current such as aperiodic component and high harmonics. The simulation results show that the proposed method can quickly identify CT saturation, position the start and end point of linear data accurately, which has simple principle, is easy to realize and has practical application value.