Awareness of the thermal conductivity of nanofluids regard to a significant development for use in research,it is necessary with regard to the inability of the analytical and experimental models that presented in most cases, it experimentally thermal conductivity can be measured. In this paper, the design and performance of thermal conductivity of fluids and nanofluidics measurement device without using a Wheatstone bridge is tested. Wheatstone bridge short transient hot wire method has previously been used for construction that requiring complex electronic systems and high power consumption. In this paper, a new method is provided so that no current or voltage is kept constant, but the method of measuring the relative resistance of the copper-clad lacquered with a diameter of 40 microns was used probe is easy to is within reach. The difference between the results of the design references, 1.17% is obtained. In this regard, changes in the magnetic fluid thermal conductivity is studied experimentally. Magnetic fluids are a new class of nanofluids are affected by magnetic fields and their properties can be changed. Fe3O4 magnetic water-based tests for different volume percentages.