Different causes of low specific gravity of urine, the danger is different, the common ones are as follows: First, a large amount of drinking plain water, mineral water, etc. in a short period of time, resulting in water diuresis, causing low specific gravity of urine, which is not harmful to the body, but if excessive water consumption can lead to water intoxication. Second, central uremia or nephrogenic uremia, can also lead to low specific gravity of urine, at this time, in addition to low specific gravity of urine, will be accompanied by an increase in urine volume, 24-hour urine volume in more than 4000ml. If not actively treated, it may lead to electrolyte disorder or kidney damage. Third, the decrease of renal tubular concentration function can also lead to low specific gravity of urine, which is common in kidney injury caused by various drugs, or early stage of hypertensive nephropathy, and low specific gravity of urine at night is more common. At this time, if not actively treated, it can lead to chronic renal insufficiency.