Abstract It have been done comparison Monokromator 270M Rapid Scanning Imaging Spectrograph / monochromator use the UV-VISIBLE Spectrofotometer SHIMADZU 1601PC by comparing result of both transmitant percentage appliance. Measurement of this percentage of transmittance (T%) Monokromator 270M got by measuring initial intensity( I0 ) and materials intensity test the ( I). From both the intensity value countable the level of the percentage of transmitansi(T%) using the formulation T = I / I0 x 100 %. Both comparison result of appliance presented in the form of graph of comparison T%. From comparison result got an accurate result for the wavelength of visible light (381-740nm). Because graph formed is continu. While for the determination of Coefficient of attenuation of materials (m) can be searched with the deferential of Lambert-Beer equation which x IILn )/( 0 -= m and got the value equal to ± 38 / (1/mm) for the sampel of spectrum 20% and equal to ± 10 / (1/mm) for the sampel of solar quard 60%. Keyword :Initial intensity(I0 ), Material intensity(I), Transmitance percentage ( T%), Lambert-Beer equation, Coefficient of attenuation(m).