This paper discusses the relationship between operator methods and matrix methods in optics. Based on the definition of optical variable operators and the hypothesis that optical operators of linear optical systems are unitary, the relation equation dealing with the relationship between operator methods and matrix methods in optics has been obtained from the general property of linear systems. For a given optical system, its optical operator can be derived from its optical matrix by solving the relation equation. And if the optical operator of a system is given, its optical matrix can also be derived from that equation. Thus the equivalency between operator methods and matrix methods in optics is demonstrated. Finally, the physical significance of the optical operator h has been pointed out.