Nerve injury may cause double lower limb weakness, including craniocerebral disease, spinal cord disease, peripheral nervous system disease, etc. 1. Craniocerebral diseases: when suffering from hemorrhage or infarction in the distribution area of the anterior cerebral artery, it can cause bilateral lower limb weakness; brain tumors can also lead to bilateral lower limb weakness. 2. Spinal cord disease: when there is spinal cord trauma or spinal cord cavity, due to the spinal cord function is impaired and motor dysfunction below the corresponding segment, the patient will feel the weakness of both lower limbs, sensory loss and so on. 3. Peripheral nervous system disease: when suffering from Guillain-Barre syndrome, the symptoms of bilateral lower limb weakness appear gradually from distal to proximal. Nerve damage can cause double lower limb weakness, it is recommended to seek medical treatment in time, after clarifying the cause of the disease, so as not to delay the condition.