After putting double J tube and hydronephrosis may be related to the displacement of double J tube and obstruction of ureteral stent tube. 1. Displacement of double J tube: after surgery, patients need to move slowly, not quickly squatting or bending, pay attention to lumbar care, not to be impacted, to avoid displacement of double J tube after pressure, puncture the bladder, kidney, resulting in bleeding, kidney drainage, so there will be a double J tube and hydronephrosis. 2. Obstruction of ureteral stent tube: it is related to the concentration of urine with little drinking water, in addition, it is also related to the urinary tract infection, the blockage of ureteral stent tube occurs, which leads to the failure of drainage of hydronephrosis, so there is a situation of releasing the double J tube and hydronephrosis. If the patient put double J tube and hydronephrosis, it is recommended to go to the hospital in time to find out the cause according to the doctor’s instructions targeted treatment.