Alveolar nerve block anesthesia precautions are for the doctor, including mastering the injection method such as injection position and depth, back to no blood before injection and so on. Patients need to pay attention to is to choose regular medical institutions to receive treatment, treatment process actively cooperate with the doctor can. 1. Block anesthesia is different from infiltration anesthesia, which is defined as injecting anesthesia drugs around the nerve trunk to block its conduction, so that the area innervated by the nerve, all lose pain. 2. Alveolar nerve block anesthesia, clinically, often includes upper posterior alveolar nerve block anesthesia, lower alveolar nerve block anesthesia. The needle point of upper posterior alveolar nerve block anesthesia is at the corresponding oral vestibular groove of the distal middle buccal root of the upper second molar, which is about 2-2.5cm deep, and it is easy to be injected into the pterygoid venous plexus when the needle is too deep, and a hematoma occurs. 3. The injection point of inferior alveolar nerve block anesthesia is about 2-3cm deep at the tip of buccal fat pad in the cheek, and it is easy to damage the facial nerve and cause facial paralysis if the injection is too deep. In addition, attention should be paid to the withdrawal of no blood before injection.