Traditional occluders for the closure of patent foramen ovale (PFO) may be associated with some potential risks, including device-related thrombus, induction of arrhythmias, residual shunt, and difficulty in puncturing atrial septum. The TriFlower device is a novel transcatheter PFO occluder that features a clamp arm design. The device success rate was 100% (n = 18) in the animal experiment. Endothelialization of the left clamp arms was completed at an early stage (30 days after implantation). The acute procedure success rate in 17 patients was 100%. At 6-month follow-up, the primary efficacy endpoint, an effective PFO closure defined as residual shunt grade 1 or lower, was met in 16 (94.1%) patients and 14 (82.4%) patients had a complete closure. There were no device-related complications. These findings indicate that the TriFlower device is feasible, safe, and effective for transcatheter PFO closure. Its potential advantages include rapid endothelialization and low left atrial interference.