Abstract: The biological functions of platelets are to participate in coagulation and to maintain the integrity of the vascular system. Thrombocytopenia occurs in a variety of hematological system diseases, radiation and chemotherapy injuries and drug-associated thrombocytopenia. It can also be a concomitant symptom of kinds of diseases, such as tumors and infections. Viral infectious diseases can lead to thrombocytopenia and its possible mechanisms mainly include decreased platelet production and increased platelet consumption. The mechanisms of thrombocytopenia caused by different viruses are also different. This article reviews the related mechanisms of thrombocytopenia in Novel Coronavirus (SARS-CoV-2), Hantaan virus, dengue virus and human immunodeficiency virus (HIV) infectious diseases, especially in recently discovered thrombotic thrombocytopenia after COVID-19 vaccination, which might provide some new ideas for the prevention and treatment of thrombocytopenia in viral infectious diseases.