Subdiaphragmatic free gas generally refers to abnormal gas outside the intestinal tube, most commonly associated with gastrointestinal perforation, if not accompanied by symptoms of abdominal pain indicates that the perforation is small or the beginning of the disease has not yet fully flared up, the symptoms are mild, and the treatment options are conservative treatment, surgical treatment, and so on. 1. Conservative treatment: some empty stomach perforation, symptoms are not serious or can not tolerate surgical treatment, can choose conservative treatment, need to fasting water, gastrointestinal decompression, broad-spectrum antibiotic application (cefepime, etc.), gastrointestinal nutritional support, maintenance of water-electrolyte balance and other treatments. 2. Surgical treatment: If the internal medicine treatment is ineffective or the symptoms worsen after treatment, surgical treatment is recommended, and omental repair, perforation repair, intestinal segment resection and so on are chosen according to the situation. When there is free gas under the diaphragm without abdominal pain, it is recommended to go to the hospital and ask the doctor to make judgment and timely treatment.