In the present work, the stability, optical property and thermal conductivity of water based mono, binary and ternary nanofluid using MWCNT, Al2O3 and ZnO nanoparticle were experimentally investigated. The mono, binary and ternary monofluid samples were prepared by two step method. A volume concentration of 0.1% and 0.4% were selected for mono and binary nanofluid samples. For ternary nanofluid the study was carried out for volume concentration varying from 0.1% to 0.4%. The stability and optical property of the samples were analyzed using the UV-Viz spectrum method. From the UV-viz spectrum the behavior of the samples to the light absorption was evaluated and the extinction coefficient of nanofluid was calculated using the Beer-Lamberts Law. It was observed that the addition of the nanoparticle increased the optical property of the nanoflud. The maximum absorbance and extinction coefficient was recorded for ternary nanofluid for maximum volume concentration of 0.4%. Thermal conductivity of all the nanofluid sample, mono, binary and ternary were measured experimentally by keeping the temperature a constant value of 25 °C. The thermal conductivity for varying volume concentration of nanoparticle were plotted against the volume concentration and it was observed from the graph that the thermal conductivity increased with the increase in volume concentration of nanoparticles for mono and binary nanofluid sample. But the thermal conductivity for ternary nanofluid was decreasing with the increase in volume concentration of nanoparticle.