Validating the existence of induced electric field;

The induced electric field produced by axial variable magnetic field with arbitrary formal interface;

A effectiveness method of calculating induced electric field;

By comparing the characteristics between induced electrical field and steady magnetic field using time vector method,the corresponding relationship between them was found out and the "Biot-Savart s" law of induced electrical field presented.

Through the discussion and analysis of the induced electromotive force, the motion caused electromotive force and the Lorentz force, it is profoundly indicated that induced electrical field force and the Lorentz force is the two different presentation of the same physics fact in the different reference systems.

In this paper the author analyses the electric potential of the conductor placed in the induced field and points out the concept cannot be introduced when the unclosed conductor is perpendicular to any direction of the induced field.