Extensional rheological properties of HDPE was measured and investigated by melt spinning techniques. It was observed that the melt strength of HDPE decreased with the rise of temperature. According to the slope of Arrhennius plots, melt strength activation energy was calculated. The curves of extensional stress and viscosity were plotted. Analysis of the results under different conditions indicated that with the rise of strain rate, the stress increased and the viscosity decreased, whereas higher temperatures yielded lower stress and viscosity. In addition, it was found that faster extrusion velocity caused lower level of extensional stress and viscosity during the experiment.