Pelvic tilt, bone and joint diseases, muscle atrophy, and neurological diseases may be the causes of this condition. 1. Pelvic tilt: The pelvis is tilted to one side because of posture or congenital developmental reasons, and when standing, the body needs to be shaken to maintain the balance of the body. In this case, the diagnosis can be clarified by taking a pelvic X-ray, and treatment can be carried out according to the causes of the pelvic tilt, for example, manipulative reset or orthopedic exercises. 2. Bone and joint diseases: Bone and joint diseases of the lower limbs can also cause shaking of the body, such as hip dysplasia or dislocation caused by the unequal length of the lower limbs, when standing, you need to swing your body to be able to stand still. Through the hip joint film can be clearly diagnosed, for the cause of the treatment. 3. Muscle atrophy: muscle atrophy caused by congenital factors or acquired trauma, imbalance of power in the lower limbs, can cause no pain in the waist but pain in standing. 4. Neurological diseases: for example, cerebral infarction or motor neuron disease can cause unfavorable activity of the lower limbs, standing will be shaking waist without pain. Therefore, you need to go to the hospital to find out the cause and further treatment.