Abstract: The cardinal points play an important role in the geometrical optics. The spread of optical imaging is analyzed when a collimated light beam passes through a compound lens，then the image rule is discussed when the rotational axis of the nodal slide does not coincident with the image nodal point，and the measurement method of cardinal points of a compound lens is presented. These can be used to deepen students ’ comprehensive understanding of the cardinal points of compound lens and measurement with nodal slide.

Key words: compound lens, geometrical optics, cardinal points, nodal slide, image rule