1, genetic factors: 30% of bedwetting children’s fathers and 20% of bedwetting children’s mothers have also committed enuresis when they were children, in turn, both parents have a history of enuresis, 40% of their sons will enuresis, 25% of their daughters enuresis, so enuresis has a hereditary nature. 2, sleep too deep: this is a more common factor, these children often play more tired before bedtime, sleep very deep not easy to wake up, also more in the dream bedwetting, if more water before bedtime is more likely to occur bedwetting. 3, mental tension: clinical statistics, family disagreement parental divorce, the loss of both parents, tragic abuse, before the entrance examination children’s chances of bedwetting increased significantly, but this urine loss is often temporary, such as mental emotional stability, will gradually disappear. 4, psychological factors: such as children psychologically think that they can not get the love of parents, loss of care, temperament is often more eccentric, shy, lonely, timid, do not get along, etc.. 5, disease factors: organic diseases involving various aspects such as nephrology, urology, neurology and psychology cause; in addition, delayed development of the cerebral cortex, which cannot inhibit the spinal urinary center, and uninhibited contraction of the forced urinary muscle after sleep, which expels urine. 6, delayed bladder function maturity: some children’s bladder is more likely to be smaller than normal children, these children usually urinate relatively more times, but not much urine, this is because there is not much urine in the bladder, it contracted to urinate.