The common causes of six-year-old babies always urinating at night are bad habits and nocturnal enuresis. 1. Bad habits: if a six-year-old baby develops the habit of drinking water before going to bed at night, he or she will always urinate at night. 2. Nocturnal enuresis: if a six-year-old baby has at least two episodes of urine leakage at night while sleeping per week for three consecutive months and central nervous system pathology is ruled out, he or she may be suffering from nocturnal enuresis. It may be caused by urinary malformations or infectious diseases of the urinary system, or it may be caused by heredity and so on. Six-year-old babies always urinate at night, there may be other reasons, it is recommended to go to the hospital, complete the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.