Abstract: Sixteen cases were obtained for the clinical analysis, which were cancerous hydropericardia, but wrongly diagnosed as pericarditis. The aymptoms were found mainly among medium and old males,whose average age was 58 years old. The male patients, who fell victims suddenly, covered 68. 75of the total cases. They felt the trouble of pericaidial tamponade, but no obvious intoxication. Of the 16 cases,there were 14, whose pericardial effusion appeared hematic. In the examination of hydrocardia cells. cancerous ones were frequently found.