Merkel cell carcinoma (MCC) is a rare, highly invasive skin tumor. In recent years, some new progress has been made in the research of MCC morphology, immunophenotype and pathogenesis. The discovery of Merkel cell polyomavirus (MCPyV) is a major breakthrough in MCC research. MCPyV-positive patients with MCC are significantly different from uninfected patients in pathogenesis, clinical characteristics and prognosis. Studies of MCPyV not only reveal some of the pathogenesis of MCC, but also contribute to exploring the tissue origin of MCC. In addition, detection of MCPyV oncoprotein antibodies in the serum can obtain prognostic information of patients with MCC. Identification of the virus status and the mutation profile of MCC tumors can better guide medication and help to develop individualized clinical treatment strategies.