Objective To study the echocardiographic characteristics in patients with cardiac lymphoma, so as to provide important information for early diagnosis and treatments. Materials and Methods The echocardiographic images and clinical data of 21 patients with cardiac lymphoma in our hospital from January 2016 to May 2022 were retrospectively analyzed. Results The most common site of cardiac lymphoma that involved were the right atrium and right ventricle; and diffuse large B cell type was the most common pathological type; the clinical manifestations were shortness of breath after exercise and chest tightness; the most common ECG abnormalities was sinus tachycardia; echocardiographic manifestations: most of the lesions were large, involving a wide range, often involving multiple parts at the same time, the internal echo was mainly hypoechoic or isoechoic, the shapes were irregular, the boundary was unclear, and the mobility was small, which could lead to valve obstruction and pericardial effusion. Extending along the epicardial surface and infiltrating into the atrium or ventricular wall, valves could be infiltrated but not invaded or destroyed, as well as vascular floating signs were the echocardiographic features of cardiac lymphoma. Conclusion The patients with cardiac lymphoma have no typical symptom, but their echocardiographic findings have certain characteristics. Echocardiography can dynamically observe the changes of cardiac tumors in early diagnosis, during treatment and follow-up after remission, which can provide important information.