The mock-up of а fiber-optic Doppler blood flow-velocity sensor has been made and described. The principle of its operation is based on the recording of the Doppler shift of scattered radiation of a monofrequent single-mode semiconductor laser. The radiation was inserted into a blood vessel model using a fiber-optic probe. The performance data of the mock-up in the blood vessel model was measured. The designed apparatus was shown to make possible the reliable measurement of the blood flow velocity in the blood vessels through inserting the fiber optic probes. The measurement accuracy depends on the accuracy of the used recording equipment. The performance data of the designed apparatus, that obtained using the blood vessel model, meets all modern requirements.