We report a case of a 42-year-old man, who presented with a three-weeks' history of dyspnea and chest oppression induced by light activity, who had a large mass in the pericardium. Computed tomography showed a non-homogeneous density lobulated mass in the pericardial sac. The tumor underwent completely resection and histopathological analysis revealed the tumor to be a pleomorphic liposarcoma, which was composed predominantly of epithelioid cells. The patient is still alive 18 months after the diagnosis was made. The rare incidence of the liposarcoma of the pericardium can easily lead to a misdiagnosis clinically, and the final diagnosis here was made histopathologically.