Abstract: Barrier pipe was made via extrusion from a blend of PE-HD, polyethylene-co-vinyl alcohol)(EVOH)，and PE-g-MAH.the effects of dosages of PE-g-MAH and processing conditions on barrier,rheological, and mechanical properties of the materials were investigated. the laminar structure of the pipe section was observed by scanning electron microscope (SEM).the barrier and mechanical property of PE-HD/EVOH pipe were better than those of PE-HD/PA6 pipe. the processing conditions for the former were easily controlled. the optimal set of recipe and processing parameters was as follows:EVOH 16一18 wt，PE-g-MAH 1一3 wt，extrusion temperature 225 C，screw rotating speed 20 r/min，and drawing ratio 1 .5一1 .6 m/min.

Key words: high density polyethylene, poly (ethylene-co-vinyl alcohol), pipe, blend, barrier property