Background: Transcatheter closure of patent foramen ovale (PFO) has been widely accepted as a highly effective way to treat high-risk PFO-related diseases. However, traditional non-degradable occluders made of metal alloys will permanently exist in the body, resulting in thrombosis, valve damage, hemolysis, arrhythmia, or other complications. The biodegradable PFO occluder developed by Shanghai Mallow Medical Instrument Co., Ltd., China can be fully absorbed and degrade into nontoxic ingredients, reducing postoperative complications. Objectives: To study the safety and efficacy of biodegradable PFO occluders in treating PFO. Methods: This single-center clinical trial collected 30 patients treated with a biodegradable PFO occluder. The follow-up period lasted 12 months to analyze the echocardiographic characteristics and headache relief through HIT-6 scores. Results: The immediate success rate was 100%, with no intraoperative severe occlusion-related complications. The contrast transcranial Doppler (cTCD) at 12 months showed that all patients' right-to-left shunts (RLS) were grade I or 0 with no serious postoperative complications, indicating the overall success rate was 100%. The biodegradable PFO occluder mostly degraded six months after the occlusion. Conclusion: PFO closure with a Mallow biodegradable occluder is safe and effective and has no severe complications.