Bariatric surgery is one of the most important treatments for obesity. Obese patients undergoing bariatric surgery are often at risk of micronutrient deficiencies. Micronutrient deficiencies can have a wide range of adverse effects on the human body, and in severe cases can be life-threatening. Adequate micronutrients are not only beneficial for postoperative weight loss, reduction of visceral fat, and improvement of metabolic health, but also have a positive impact on liver function, blood lipids, and Glycosylated Hemoglobin (Type A1C, HbA1c). This article describes two aspects of micronutrient deficiencies and micronutrient supplementation strategies in patients undergoing bariatric surgery, with the aim of providing a reference for screening, supplementation, and prevention of micronutrient deficiencies in patients undergoing bariatric surgery.