Subarachnoid hemorrhage can be examined by the following means: 1. physical examination, mainly checking the patient’s meningeal irritation sign, observing whether the patient has cervical tonicity and stiffness, how many transverse fingers of the jaw from the chest, and whether the Gram’s sign and Brønsted’s sign are positive. 2. imaging examination, mainly relying on cranial CT, can also perform cranial magnetic resonance examination, but CT will be more sensitive. CT can detect high-density shadowing in the subarachnoid space, but if the hemorrhage is prolonged and blood and cerebrospinal fluid in the subarachnoid space are mixed, the high-density shadowing may not be obvious enough. 3.Lumbar puncture is the gold standard to confirm the diagnosis of subarachnoid hemorrhage, there are no red blood cells in the cerebrospinal fluid, if red blood cells can be found by lumbar puncture and puncture injury is excluded, the diagnosis can be confirmed. Subarachnoid hemorrhage can be diagnosed by performing a triple tube test to determine whether it is a puncture injury.