A smart tourniquet includes a casing having a control unit； a contact area arranged to the casing, configured to contact a patient's skin, and connected to the control unit； a cuff arranged to the casing with an inflatable bladder； an adjustable strap arranged to the cuff for securing the cuff and casing to the patient； a pump contained in the casing, connected to the bladder, and controlled by the control unit； a thermoelectric module contained in the casing, controlled by the control unit, and connected to the contact area； and at least one sensor contained in the casing for detecting blood pulse and controlled by the control unit. The control unit is configured to inflate and deflate the bladder in response to blood pulse for changing a pressure around an arm or leg and to heat the contact area for vasodilating a vein under the patient's skin for visual detection.
