The authors investigate thermal and dynamic performance of zinc oxide nanofluid on the heat pipe with 0.2 m in length and 0.006 m in diameter in this paper. Two types of zinc oxide nanoparticles with average size of 35 and 55 nm are used in this study. The experiments are conducted to measure and compare temperature, thermal resistance, pressure drop and pumping water of pure water and zinc oxide nanofluid which fills heat pipes. Temperature values are measured in different length of pipe and thermal resistances are obtained in different power. The pressure drop and pumping power are measured in different Reynolds number. The experiments are conducted for pure water and non-pure solutions with variable concentrations that are among 1mg/l to 100mg/l . The experiments show the thermal resistance decreased 15 to 66 percentages when zinc oxide nanoparticles are added to pure water at an input power of 30Â60 Watt. In addition, the experimental results showthat the thermal resistances of the heat pipe decrease as the size and concentration of zinc oxide increase. The experimental data show that required pumping power and observed pressure drop are increased with the increasing of Reynolds number values and concentration of zinc oxide nanofluid. Comparison of pressure drop values in pure water with that are observed in non-pure solution, 50 mg/l nano zinc oxide with 55 nm in size, show that maximum amount is 80%. Themaximumdeviation between amount of pumping power in purewater and non-pure solution,with 100mg/l zinc oxide nano particles with 55 in diameter, is recorded 92%approximately and this value is related to dual effect of increase in both the pressure drop and the concentration of non-pure solution.