Abstract: Nineteen cases of rare types malignant mesothelioma were studied by light mi-croscopic,electron microscopic, immunohistochmicall and histocbemicall stainings.The resultsshowed that malignant mesothelioma may be new histologic subtypes, including signet ringoidcell, small cell myxoid, myofibroblastic cell, lymphohistiocytoid, angioblastic cell and undifferen-tiated types. Diagnosis critera of malignant mesothelioma of rare types were briefly discussed.