Semantic Web data proliferates with the rapid growth of the semantic Web. An object on the semantic Web is likely to be denoted with many identifiers (e.g., URIs) by different parties. Resolving an object coreference on the semantic Web is to identify different identifiers for the same object and eliminate the inconsistency between their involved RDF (resource description framework) data, which is important for semantic Web data fusion, search, browsing, etc. In this paper, the problem of resolving object coreference on the semantic Web is first formalized. Next, the state of the art of works are surveyed and categorized into five aspects: The used characteristics for coreference identification, the mechanisms for data conflict resolution, the applicable scopes of current approaches, prototypes, and benchmarks. Finally, open research issues are discussed and possible future research directions are also pointed out.