Metallic colloidal particles- semiconductor thin films show special electrical, optical and photoelectric properties. The formulas for light absorption coefficient and scattering coefficient of small colloidal particles dispersed in semiconductor thin film are given in this paper. The colloidal particles may be spheroids, prolate spheroids or oblate spheroids. As an example, the effects of sizes and shapes of Ag colloidal particcles in Ag-Cs2O semiconductor thin films on light absorption and scattering are discussed. The calculated curves for relative absorption coefficient and scattering coefficient vs. wavelength λ are also presented.