In this paper, the thermal conductivity and electrical conductivity of SiO2 nanofluids using mixture of ethylene glycol (EG) and water (HO2) as the base fluid are investigated. The two-step method was used to prepare SiO2-EG/H2O nanofluids with a mass concentration of 0.3%. The variations in thermal conductivity and electrical conductivity as functions of EG concentration (0-100%, v/v) and temperature (25-45 degrees C) are present. Experimental results showed that the thermal conductivity and electrical conductivity of SiO2-EG/H2O nanofluids both decreased as the EG content percentage increases in the EG/H2O mixture. At a specific EG content percentage, thermal conductivity and electrical conductivity both increased with the increase in temperature. To better evaluate the enhancement performance of SiO2-EG/H2O nanofluids, the relative electrical conductivity was introduced and studied explicitly. The mechanism of electrical conductivity enhancement in SiO2-EG/H2O nanofluids was analyzed in detail. Meanwhile, the ratio of thermal conductivity and electrical conductivity was also discussed. (C) 2017 Published by Elsevier Ltd.