Numbness of the left little finger may be caused by physiological factors, injury, ulnar neuritis, cervical spondylosis, diabetic peripheral neuropathy and other factors. 1. Physiological factors: for example, the left little finger is compressed for a long time, so that the blood flow is not smooth, which will lead to numbness of the little finger, and can be recovered by itself after the compression is lifted. 2. Injury: the left side of the little finger suffered injury, such as heavy objects, nerve damage, will lead to the right side of the little finger numbness, may also be accompanied by the little finger activity is limited, pain, swelling and other symptoms. 3. Ulnar neuritis: it may be related to trauma, ulnar nerve dislocation, swelling compression and other factors, which can induce ulnar neuritis, which will cause numbness of the left little finger, and may be accompanied by hand weakness, inflexibility and other symptoms. 4. Cervical spondylosis: for example, cervical spondylosis of the nerve root type, which may be related to prolonged work, neck trauma and other factors, resulting in damage to the nerves innervating the upper limbs, which will cause numbness of the left little finger, accompanied by numbness of the left upper limb, radiating pain and other symptoms. 5. Peripheral neuropathy: prolonged diabetes may lead to peripheral neuropathy, which may cause numbness in the little finger, accompanied by symptoms such as hyperalgesia. Numbness of the left little finger, and accompanied by other abnormal symptoms, it is recommended that the patient seek medical treatment in time to avoid delay in treatment.