Colonic mucosal pseudolipomatosis，presenting as scattered multiple white plaques throughout the colon, is a rare complication of colonoscopy. Damaging of overaeration, mechanical torsion or residual peroxides during colonoscopy lead to pneumotosis of lamina propria and formation of mocusal "snow white". Endoscopists should fully understand this disease to avoid misdiagnosis and unnecessary reperted endoscopic examination.