Subarachnoid anesthesia, also known as lumbar anesthesia, is widely used clinically for surgical anesthesia of the lower abdomen and lower extremities, and is characterized by rapid onset of action, perfect analgesia, and good muscle relaxation, which is beneficial to the surgeon’s surgical operation. Because the lower segment of the spinal cord in adults generally terminates at the lower edge of the lumbar 1 vertebra or the upper edge of the lumbar 2 vertebra, lumbar anesthesia is usually chosen in the lumbar 2-3 or lumbar 3-4 as the puncture point, and the sign of successful puncture is the outflow of cerebrospinal fluid, and when the outflow of cerebrospinal fluid is seen, the anesthetic drug can be injected. The commonly used anesthetic drug in clinical practice is bupivacaine or ropivacaine, which is often prepared with 5%-10% dextrose solution. After the local anesthetic is injected into the subarachnoid space, the level of anesthesia needs to be adjusted to the surgical needs, and the level is fixed after 5-10 minutes. Because of the outflow of cerebrospinal fluid from lumbar anesthesia, which leads to the reduction of intracranial pressure and intracranial vasodilation and causes vascular headache, patients should lie down after anesthesia to minimize the leakage of cerebrospinal fluid and avoid the occurrence of postoperative headache. Because the parasympathetic nerve fibers innervating the bladder are very thin and recover late after the block, urinary retention is likely to occur. Close observation is required after surgery, and a catheter can be left in place if necessary.