Annealed Nd0.7Ca0.3MnO3 samples (untreated, 700oC, 800oC and 900oC) were investigated by solid state reaction method. Studies happened into the variations in The optical parameters of NCMO samples, that were calculated from measurements of reflectance obtained with a spectrophotometer. Studies occurred on the associations between photon energy and absorption coefficient. The study showed that the optical transition is indirectly transition. The highest energy gap for as prepared NCMO is about 4.2 eV which makes the compound used as a absorber of the solar system applications, the study gives us the values of the refractive index, real part of the dielectric constant, the imaginary part of the dielectric constant and tan(d) of unheated and 700, 800, 900 o C samples, in addition the optical conductivity was measured.Annealed Nd0.7Ca0.3MnO3 samples (untreated, 700oC, 800oC and 900oC) were investigated by solid state reaction method. Studies happened into the variations in The optical parameters of NCMO samples, that were calculated from measurements of reflectance obtained with a spectrophotometer. Studies occurred on the associations between photon energy and absorption coefficient. The study showed that the optical transition is indirectly transition. The highest energy gap for as prepared NCMO is about 4.2 eV which makes the compound used as a absorber of the solar system applications, the study gives us the values of the refractive index, real part of the dielectric constant, the imaginary part of the dielectric constant and tan(d) of unheated and 700, 800, 900 o C samples, in addition the optical conductivity was measured