A 65-year-old female presented to our center with exhaustion and shortness of breath after daily exercise for two months. On physical examination, vital signs were stable. All laboratory results were unremarkable. Transthoracic Echocardiogram showed a round hypoechoic mass (2.3cm  2.6cm) under the tricuspid valve with clear margins, part of which closely connected with the right ventricular wall (Figure 1 A) and there was no blood flow signal inside (Figure 1 B). The mass does not communicate with the heart’s chambers and can affect blood flow in the inflow tract of the right ventricle. Contrast-enhanced computed tomography revealed a low-density round mass in the right ventricle, and it does not enhance after the injection of intravenous contrast media (Figure 1 C). The patient underwent right ventricular mass resection under cardiopulmonary bypass. The tricuspid valve was suspended during the operation to expose the cyst below the tricuspid valve. The cyst wall is almost transparent (Figure 1D). Approximately 7 ml of pellucid fluid withdraw with a syringe from the cyst (Figure 1 E1). Then the exposed cyst wall was then wholly resected (Figure 1 E2), but part of the cyst wall is the wall of the right ventricle, this part cannot be removed. The patient had an uneventful postoperative recovery. Histopathological examination revealed that the cystic wall was covered by low cuboidal epithelium, and the cystic wall was glassy fibrous tissue, consistent with cystic changes (Figure 1 F). The right ventricular watery cyst is a rare intracardiac cyst that can easily be mistaken for a myxoma. Whether such cysts will recur is worthy of our long-term follow-up attention.