Left leg can not feel hot and cold, and burning sensation may be lumbar spine disease, diabetes, lower extremity vascular lesions and other factors. 1. Lumbar spine disease: for example, lumbar disc herniation, severe cases may compress the nerves that innervate the lower limbs, which will lead to numbness in the left leg, loss of sensation, accompanied by a burning sensation, there may also be lumbar pain, hip pain and other symptoms. 2. Diabetes mellitus: when suffering from diabetes mellitus, the continuous increase of blood glucose may lead to peripheral neuropathy, resulting in nerve damage, which will lead to hypesthesia and burning sensation of the left leg, and in severe cases, ketoacidosis may also be caused. 3. Lower extremity vascular disease: for example, varicose veins, vasculitis, etc., may lead to lower extremity blood flow obstruction, which will lead to the left leg sensory impairment, and there is also a burning sensation, swelling and other symptoms. The left leg can not feel hot and cold, and burning sensation may have other reasons, it is recommended that the doctor for a detailed examination, to clarify the specific causes of the disease, follow the doctor’s instructions in a timely manner targeted treatment to avoid aggravation of the lesions.