Background　Transcranial doppler （TCD） is an examination for cerebral blood flow dynamics characteristics. It can be used to monitor the change of cerebral blood flow velocity in the process of anesthesia and the formation of blood clots， to provide information for brain protection. It has the advantages of easy operation， real?蛳timing and continuous monitoring.　Objective　To introduce the application and progress of TCD in perioperation recently.　Content　TCD can provide relevant information， such as blood flow velocity， pulse rhythm change， vascular stenosis and thrombosis， intracranial pressure， etc.　Trend　With lots of advantages， TCD for perioperative period has broad prospects in the future.