As a part of studies on the phonological system across the entire Eastern Han time(“EH” hereafter), this study is designed to reveal the types and sorts of the clusters as reflected in the annotations of Zheng Xuan, one of the outstanding scholars of that time. EH stands at the later stage of Old Chinese(“OC” hereafter). The “Initial Consonant Clusters”(“clusters” hereafter) in the Earlier stages of OC, i.e. the pre-Qin time, are claimed to be abundant, but they gradually reduced in numbers and types over time and all of them had finally turned into simple initials before Middle Chinese. As simplification of the clusters may have been taking place in EH, it would be significant to study what types or sorts of clusters were retained in EH. And there also existed a number of useful materials which enable us to tell much about the phonology of that time. We take Zheng-Zhang Shangfang’s OC Phonology as a point of departure. We find some of his transcriptions on some characters problematic and thus attempt to revise them by providing some evidence revealed in phonetic components[諧聲], yiwen[異文], tongjia[通假] as well as phonetic correspondences with other cognate words of Chinese or words of other genetically related languages. We find that some types of clusters which originated from Early OC are no longer reflected in his annotations while Cl- is the most usual type among those which existed in his annotations. We also find the other types and sorts retained in them, such as Sc-, hN-, sCl- and other trivial ones. That, however, does not necessarily mean that all of the clusters which are not reflected in his annotations had completely disappeared as of his time. This study may provide only a sketchy description of the clusters of the time, and we expect that further studies along with this one against all sorts of extant annotations and materials will help us to trace the history of phonology of EH.