The discrete self-imaging effect reveals the distinct properties of cladding modes with core modes in step-index optical fibers, as was shown in our previous work [1], where only the linearly polarized LP 0n modes were studied. In this paper, the dispersion diagram of the first 17 vector modes (TE 0n , TM 0n , HE mn and EH mn ) and the related first 9 LP mn modes are calculated by both the full-vector finite element method and the graphical method with a three-layer step-index optical fiber model. The cladding modes distributions and the transitions between the core and cladding modes are analyzed. The results of this work are intended to enrich the knowledge and understanding of modal characteristics of conventional step-index optical fibers.