The opt-mechanical design of a Spectrally-Continuous Radiometer (SCR) for surface reflectance automation observation was described. Operating in 400~2 400 nm, the SCR can automatically measure the surface reflectance of radiometric calibration site to get continuous and hyperspectral reflectance data. A calibrated white diffused panel was used as the reflectance standard, and the panel was cut into and out of the optical measurement path through a rotatable mechanical arm. An air-cleaning mechanism was designed to keep the panel clean which is very important for the long-term applicability of the SCR in the field. The static analysis was carried out for the rotating arm using the static structural module of ANSYS WORKBENCH, because the roating arm is prone to failure. The results showed that some stress concentrations located at the rotating shaft position, the deformation was larger as farther away from the rotating shaft, and the maximum deformation can caused a inclination within 0.3°. To verify the accuracy and reliability of the SCR, experiment was carried out with SCR and SVC. The results showed that the reflectance measured with two devices had the same trend, the deviation was generally within ±1%, and the maximum deviation was within ±3.5%, which demonstrated that the SCR could achieve highly accurate reflectance data in automation manners and have broad application prospects in field-based automation calibration and high-frequency calibration for satellite-based remote sensors.