Hydronephrosis is often caused by urinary tract obstruction due to various reasons, which leads to urine retention. Prevention of hydronephrosis should mainly focus on preventing the occurrence of urinary tract obstruction, such as surgical treatment of urethral strictures and other diseases, eradication of urinary tract infections, especially those bacteria that break down urea to avoid foreign bodies in the bladder and reduce the occurrence of stones. Eliminate urinary tract obstruction factors, such as for congenital urinary tract abnormalities should be actively dealt with. If the narrowing of the prepuce and urethral opening is found early, it should be lifted in time. In case of trauma and inflammation, inflammation should be promptly controlled and urinary tract infection should be thoroughly treated to prevent the occurrence of urinary tract obstruction. For patients with urinary tract stones, prevention should pay attention to the following measures: 1, review once every six months, increase exercise, long-term bedridden people should be turned often. 2, drink a lot of water urolithiasis patients such as increasing the volume of urine by 50%, the incidence of urinary stones will be reduced by 86%, especially before going to bed to drink more water to develop the habit of drinking water to maintain a daily urine volume of not less than 2000-2500ml. 3, regulate the diet of calcium oxalate stones patients should eat less spinach, reeds, tofu chocolate and other foods containing more oxalic acid or calcium; calcium urate stones patients should avoid eating meat, crabs, spinach, animal viscera Such as liver, brain, kidney, etc. 4, actively treat all kinds of infectious diseases. 5, should not be long-term use of sulfonamide, acetazolamide and other drugs that can easily cause urinary crystals.