Method for operating a device of blood analysis includes: according a photoelectric transducer to detect a blood vessel to bring a sensor signal according a processor to receive the sensor signal and to execute a judgment procedure. At the judgment procedure, the processor transforms the sensor signal to a data of vascular flow. When the data of vascular flow located at a basis flow range, the processor brings and output a drive signal, else executes the judgment procedure continuously and according a ultrasonic sensor to receive the drive signal, it detects the blood vessel and brings a data of vascular caliber. Such as, the present invention has to improve detection efficiency.一種操作血管分析裝置的方法,包含:以一光電式感測器感測一待測血管並產生一感測訊號;以一處理器接收該感測信號並執行一判斷程序,在該判斷程序中,該處理器係將該感測信號轉換為一血管流態資料,並判斷該血管流態資料是否位於一基準流態範圍內,若是,則產生並輸出一驅動訊號,若否,則持續執行該判斷程序;及以一超音波偵測器接收該驅動訊號,偵測該待測血管並產生一血管口徑資料,藉此具有提升檢測效率的效果。1‧‧‧光電式感測器2‧‧‧處理器3‧‧‧超音波偵測器4‧‧‧顯示器15‧‧‧無線傳輸模組21‧‧‧無線收發模組
