Left kidney stones combined with left hydronephrosis need to be examined and evaluated in the hospital to clarify the cause and treat the symptoms.1. Primary kidney stones on the left side, resulting in secondary hydronephrosis. At this time, the stone needs to be treated, and the fluid accumulation can be relieved naturally after the stone is treated. In this case, the stone causes obstruction to the outlet of the renal pelvis and ureter, and the urine produced by the kidneys can not be discharged smoothly, resulting in the manifestation of fluid retention. After extracorporeal shock wave lithotripsy or surgical treatment to remove the stone obstruction in the body, the fluid can be discharged into the bladder through the ureter on its own and be relieved without the need for any medication or surgical treatment.2. Primary hydronephrosis on the left side combined with secondary renal stones on the left side, you need to deal with the fluid and then deal with the stone or deal with the stone and the fluid at the same time. Due to the obstruction in the urinary system, the fluid firstly leads to the accumulation of fluid, and over time, the material inside the accumulation of fluid deposits and precipitates to form stones. If the stones are treated alone, the fluid retention will not be effectively relieved after the surgery. It is necessary to identify the cause of the fluid retention and treat the cause of the problem in order to achieve a complete cure.