Primary pericardial mesotheliona is a clinical rarity. 7 cases were reported in this paper. There were no typical clinical symptoms and signs. It could not be diagnosed simply with chest film, ECG or echocardiagram and was usually misdiagnosed as constritive pericarditis, tuberculous pericarditis etc. In order to make correct diagnosis, some investigative diagnose methods such as pathological examination of pericardial fluid and pericardial biopsy, Gallium-67 scintigraphy, Ber-EP4 antibody and immunohistochemical procedures should be employed.