We demonstrate experimentally the Doppler cooling of 40Ca+ ions using the S1/2 → D3/2 electric quadrupole transition,in which the scattering light that is much different from the exciting light makes it possible to collect background-free fluorescence.The idea excluding 397nm excitation has the advantage of high-sensitivity detection and only employs lasers in red and infrared wavelengths,which should be practical for trapped-ion quantum information processing.