Zero reflectance conditions for an absorbing thin film coated on metal substrate are inferred based on Fresnel equations. The required film thickness as well as the complex refractive index range are deduced. Based on such consideration, a thermal control coating with special selective absorbing characteristic was prepared by reactively sputtering NiCrOx absorbing him on stainless steel substrate. The optical constants of this NiCrOx film are measured and the required film thickness is calculated. The spectral reflectance of the tandem was measured in the wavelength range of 0.3-25 mum, which shows a near zero reflectance at 0.8 mum and a high reflectance at infrared. The solar absorbance is 0.8 while normal emittance is 0.14.