There are many causes of numbness in the left foot, and the treatment plan is different according to the cause, the common causes are mainly the following: First, lumbar spine disease can compress the sciatic nerve causing numbness and pain in the lower limbs, improve the diagnosis of lumbar spine related examination, treatment is mainly through acupuncture, physical therapy to relieve symptoms. Secondly, diabetic peripheral neuropathy can cause lower limb numbness and sensory abnormalities, which can be clearly diagnosed through blood glucose measurement and electromyography examination. Thirdly, cerebrovascular diseases can also cause the above symptoms, such as cerebral infarction and cerebral hemorrhage, which can be accompanied by impaired limb movement and swallowing dysfunction, etc. The diagnosis can be clarified by perfecting relevant head examinations.