Bariatric surgery may cause intestinal microecological environment imbalance due to changes in gastrointestinal anatomy.Some patients may have compli-cations,even regain weight.Probiotics can act on intestinal mucosa,epithelium and gut-associated lymphoid tissue to improve the intestinal microecological environment of obese patients after bariatric surgery.Probiotics can promote the production of short-chain fatty acids,stimulate intestinal cells to release glucagon-like peptide-1,peptide tyrosine-tyrosine,insulin and other endocrine hormones,affect the function of the central nervous system through the gut-brain axis,make patients after bariatric surgery feel full,and reduce blood sugar at the same time.Probiotics can produce lactic acid,acetic acid and lactase,to inhibit the growth of harmful bacteria and to improve gastrointestinal symptoms of patients after bariatric surgery.Probiotics can activate the AMP-activated protein kinase signaling pathway,improve lipid metabolism,and promote the recovery of symptom indicators of nonalcoholic fatty liver disease after bariatric surgery.Probiotics can regulate the release of neurotransmitters or metabolites by the microbiota through the gut-brain axis to affect brain activity and behavior,thus helping patients improve negative emotions after bariatric surgery.This article describes the intestinal microecological environment of obese patients and mechanism of the change after bariatric surgery and summarizes the effects and possible mechanisms of probiotics in improving the intestinal microecological environment of obese patients after bariatric surgery,to provide references for promoting the clinical application of probiotics.