The main causes of the patients’ left leg hot and right leg cold include peripheral vascular diseases and neurosensory abnormalities. 1. Peripheral vascular disease: refers to the diseases that cause abnormal peripheral circulation due to various reasons. Poor blood circulation leads to the situation that the patient’s left leg is hot and the right leg is cold. Common diseases such as lower extremity venous circulation disorders, varicose veins of the lower extremity, arterial vascular occlusion and so on. 2. Nerve sensory abnormality: It refers to the disease of nerve compression or the lesion of the nerve itself. This kind of disease will lead to abnormal body sensation, and there may be sensory disorder on one side of the limbs, and the situation of hot left leg and cold right leg will occur. Common diseases such as lumbar disc herniation, lumbar spondylolisthesis, and even tumors inside and outside the spinal canal, etc., will oppress the nerves. The left leg is hot and the right leg is cold, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.