1. Pay attention to drink a lot of water to increase the solubility of cystine, ensure the daily urine volume is above 3000ml, i.e. drink at least 150ml/h. 2. Alkalize the urine to make the pH of urine reach above 7.5. You can take sodium potassium hydrogen citrate (Youlait) 1~2g, 3 times/d. 3.It is advisable to consume more low protein diet based on vegetables and cereals, and avoid excessive consumption of foods rich in methionine (soy, wheat, fish, meat, beans and mushrooms, etc.), low protein diet can reduce the excretion of cystine. 4.Limit the intake of sodium salt, the recommended sodium salt intake is limited to 2g/d or less. 5.When urinary cystine excretion is higher than 3mmol/24h, apply thiopronine (α-mercaptopropionylglycine) 250~2000mg/d or captopril 75~150mg/d.