A nanofluid is a fluid containing suspended solid particles, with sizes on the order of nanometers. Normally, nanofluids have higher thermal conductivitiest han their base fluids. Therefore, we measured the thermal conductivity and viscosity of oxidized carbon nanofluids based the mixture of distilled water and ethanol (ethanol concentration is 0.2) oxidized carbon nanofluids were made by ultrasonic dispersing oxidized multi-walled carbon nanotubes in the mixture of distilled water and ethanol at the rates of 0.001~ 0.1 vol%. The thermal conductivity and viscosity of oxidized carbon nanofluids were measured by using transient hot-wire method and rotational digital viscometer, respectively. And all of experiments were carried out at the same temperature conditions($10^{circ}C$, $25^{circ}C$ and $70^{circ}C$). As a result, when volume fraction of nanofluids is 0.1 vol%, thermal conductivity was improved 13.6% ($10^{circ}C$), 15.1% ($25^{circ}C$), and 17.0% ($70^{circ}C$), and its viscosity was increased by 36.0% ($10^{circ}C$), 32.9% ($25^{circ}C$) and 19.5% ($70^{circ}C$) than the base fluids.