The causes of pain in the left side of the waist of women are generally lumbar muscle strain, pancreatitis, kidney stones and so on. 1. Lumbar muscle strain: women’s waist left side pain may be a long time sitting or standing for a long time, due to a long time to maintain a posture, so that the lumbar muscle lactic acid gathered, seriously affecting the normal metabolism, and ultimately the formation of lumbar muscle strain, triggering women’s waist left side pain. The pain can be treated with ointment or painkillers when the pain is severe. 2. Pancreatitis: A large amount of pancreatic fluid seeps into the abdominal cavity after acute severe pancreatitis, causing necrosis of the peripancreatic tissues and thus causing pain in the left side of the waist. Through rehydration, anti-infection and inhibition of pancreatic enzyme secretion, the symptoms of pancreatitis can be reduced and the pain relieved. 3. Kidney stones: If the left urinary stone is embedded in the middle and upper part of the ureter, it will lead to obstruction of urinary excretion, dilatation of the upper part of the ureter, and hydronephrosis on the left side of the renal pelvis. Urologic ultrasound and CT examination are needed to clarify the condition and treat the symptoms to relieve the pain symptoms. Women with pain on the left side of the waist need to seek timely medical attention to identify the cause and treatment.