It's very difficult to study high-strenth compositesbecause of the poor adhesion of polyethylene fibres caused by its specialstructural qualities.This paper reports a study of changing the surfacequalities of ultra high molecular weight polyethyene(UHMW-PE)fibres of different draw ratios by plasma and acid treatment.It alsodevotes to the experiments of measuring the fibre resin adhesion bythe pull out technigue,and studies the mechanism of the interface failureby SEM.The experimental results show that there's a significant impr-ovement in the adhesion between the UHMW-PE fibres and the resinafter the plasma treatment and it can be four times stronger,dependingupon the draw ratios of fibres and plasma parameters,The interfacefailure in the pull-out test involved developes along the fibre-resininterface within the fibre,and the skin of the fibre is peeled off.Theadhesion can be improved by combining the plasma etching technique andother methods of treating the surface of UHMW-PE fibre.