Dietary precautions after open heart surgery vary according to the time after surgery. Fluid and semi-fluid food is recommended for a few days after surgery, and easy-to-digest food is recommended after about a week after surgery. Generally, on the day after surgery, eating and drinking are prohibited, and bed rest is timely. When the effect of anesthesia drugs completely disappeared and anal defecation appeared, the patient can enter a liquid diet, such as rice soup, thin rice, etc., and then gradually transition to a semi-liquid diet, such as noodle soup, millet porridge, etc.. When discharged from the hospital, patients are advised to increase nutrition, meat and vegetables, eat more high-quality high protein, such as lean meat, eggs, milk; high vitamin food, such as animal liver, fresh fruits and vegetables; easy to digest food, such as pasta, millet porridge, corn mush; dietary fiber-rich food, such as fresh vegetables, fruits, such as celery, leeks, apples, bananas and so on. Eat a light diet and avoid excessive greasiness. Postoperative diet is recommended to eat small meals, and to slow down the speed of eating, too fast diet will increase the burden on the gastrointestinal digestive tract, at the same time will make the blood sugar rise too fast, also not conducive to digestion, chewing and slow swallowing is conducive to smooth defecation, to prevent constipation, postoperative patients should be gradually transitioned from eating small meals to regular quantitative. Other precautions should follow the doctor’s instructions.