HDPE/ EVA blend was prepared by thermal mechanical blend method，and the rheological behavior of the prepared blend was studied with capillary rheometer. The results show that the blend is a pseudoplastic fluid，the apparent viscosity of the blend decreases with the increase of the shear rate and shear stress and with the rise of temperature. The viscosity-flow activation energy of the blend tends to decrease with the increase of shear rate and the content of EVA. Aiming at the relationship between the viscosity and the component ratio，the predicted values of Hashin model and Heitmiller model matched the experiment results well，while the error of Taylor model is much bigger.