Provided is a method of using gasbag armband to evaluate function of flow-artery by vasodilation, which includes the steps of: providing a processing unit； preparing a digital gasbag armband device arranged therein a gasbag armband, a pressure sensor and a flow sensor, and provided with a sphygmomanometer function； using the digital gasbag armband device to measure the status of brachial artery before blood blocking, so as to obtain a first vibration wave by means of the pressure sensor and transmit the same to the processing unit； using the digital gasbag armband device to perform a blood blocking operation and using the digital gasbag armband device to measure the status of brachial artery after blood blocking, so as to obtain a second vibration wave by means of the pressure sensor and transmit the same to the processing unit； and using the processing unit to convert the first vibration wave and the second vibration wave into a first artery volume change amount wave and a second artery volume change amount wave by means of a transfer function constituted by the pressure sensor and the flow sensor, and performing a comparison on each portion of the two volume waves to output a ratio of the difference.一種氣囊臂帶評估動脈血流介導血管舒張功能的方法，包含有如下步驟：提供一處理單元；取用一數位式氣囊臂帶裝置，有一氣囊臂帶，一壓力感知器及一流量感知器設於裝置中，該裝置並具有血壓計功能；以該數位式氣囊臂帶裝置量測阻血前的肱動脈狀態，藉由該壓力感知器取得一第一壓振波傳送至該處理單元；以該數位式氣囊臂帶裝置進行阻血動作，以該數位式氣囊臂帶裝置量測阻血後的肱動脈狀態，藉由該壓力感知器取得一第二壓振波傳送至該處理單元；該處理單元透過壓力感知器及流量感知器所建構的轉換函數，將第一壓振波與該第二壓振波轉換為第一動脈體積變化量波與第二動脈體積變化量波，比較兩體積波的各一部分，並輸出其差異值得比值。
