It is normal for a nine-month-old baby to urinate about 4 to 6 times in 24 hours, but the exact number of times he or she urinates is related to the amount of water the baby drinks. In general, a nine-month-old baby should urinate 4~6 times a day. If the baby drinks more water, the number of urination will increase; if the baby drinks less water or eats more, the number of urination will decrease. These are normal phenomena. It should be noted that if the baby has an unexplained increase in the number of times of urination or a decrease in the number of times of urination, it must attract the attention of parents, may be suffering from uremia, acute renal failure and other diseases, it is recommended to take the child to the hospital as soon as possible to pediatrics or urology department, to clarify whether the baby suffers from urinary system diseases.