We reported a very rare case, a 59-year-old female whose heart myxoma was present in both atrium, the mass in biatrial was connected to each other at the oval foramen, resembling "dumbbell-like." By means of multimodality echocardiography techniques such as transthoracic echocardiography (TTE), contrast enhanced ultrasound (CEUS), and Real-time three-dimensional transesophageal echocardiography (RT-3D TEE), we have clarified the diagnosis. The patient underwent open-heart surgery to remove the biatrial myxoma which adhered to the oval fossa, with a slightly wider base and smooth lobulated surface. This case demonstrates the importance of multimodality echocardiography in the diagnosis of atypical myxomas.