Intermediate syndrome is a group of clinical syndromes with muscle weakness of the proximal limbs, muscle weakness of cerebral innervation, and respiratory muscle paralysis as the main symptoms. 1. Weakness of proximal muscles of the limbs: it manifests as weakness of the limbs, difficulty in lifting, decreased grip strength of both hands, decreased muscle tone of the limbs, weakened or disappeared tendon reflexes, and no sensory impairment. 2. Weakness of muscles innervated by cerebral nerves: manifested as difficulty in puffing up the cheeks, limitation of eye movement and tremor, difficulty in chewing and swallowing, unclear pronunciation, difficulty in turning the head and shrugging the shoulders. 3. Respiratory muscle paralysis: manifested as dyspnea, chest tightness and suffocation, cyanosis of lips and mouth, increased respiratory rate, and in severe cases, respiratory failure may develop and cause death. It should be noted that cardiovascular disease also has the term intermediate syndrome, the performance is similar to angina pectoris. The intermediate syndrome is common in acute severe organophosphorus pesticide poisoning, with a variety of clinical manifestations, rapid progression and viciousness, and attention should be paid to early detection, early rescue and early treatment.