Spectral absorbency analysis is another technique for measuring nanofluid stability. The absorbency intensity and nanoparticle concentration in fluid have a linear relationship in general. After the suspensions had been deposited for 24 hours, the dispersion characteristics of alumina and copper suspensions were investigated using the traditional sedimentation method and absorbency measurements with a spectrophotometer. To analyze sedimentation kinetics, the absorbance of particles in solution might be employed.UV-vis spectral analysis provides a simple and effective approach for analyzing the stability of nanofluids when nanoparticles scattered in fluids display discrete absorption bands in the wavelength range 190–1100 nm. Because the concentration of supernatant nanoparticles and the absorbance of suspended particles have a linear relationship, the variation of bouncy particle content in nanofluids with sediment time may be calculated by measuring absorption of nanofluids. When compared to other methodologies, UV-vis spectral analysis has the specific advantage of displaying the quantitative concentration of nanofluids.