A blood vessel-positioning device includes an IR camera unit, an image-processing unit and an image projector unit. The image-processing unit connects with the IR camera unit and the image projector unit. The IR camera unit is operated to capture an IR image at a predetermined position. The image-processing unit is configured to process the IR image to obtain at least one temperature feature of an area which is calculated to obtain blood vessel positions or blood vessel depths. The blood vessel positions or the blood vessel depths are converted into images of blood vessel positions or blood vessel depths which are projected to the predetermined position with a predetermined projection mode.一種血管定位裝置包含一紅外線影像感測組、一影像處理單元及一影像投影單元。該影像處理單元連接於該紅外線影像感測組及該影像投影單元。該紅外線影像感測組於一預定位置感測取得一紅外線影像。利用該影像處理單元演算處理該紅外線影像,以便尋找至少一區域溫度特徵,再將該區域溫度特徵進行演算處理,以獲得一血管位置或一血管深度,並將該血管位置或血管深度轉換成一血管水平位置影像或一血管垂直深度影像,且將該血管水平位置影像或血管垂直深度影像以一預定投影模式投影至該預定位置上。11‧‧‧第一紅外線影像感測組12‧‧‧第二紅外線影像感測組20‧‧‧影像處理單元30‧‧‧資料儲存單元40‧‧‧影像輸出單元
