Abstract: The poor adhesion of ultra-high molecular weight poly-ethylene fibres to epoxy resin due to the characteristics of their surface structure makes it difficult to develop light composite materials with good mechanical properties.In this paper the low-temperature plasma was applied to treat the surfaces of the fibres.The results show that the surface en ergy of the treated fibres increases greatly so that the fibres can be wetted very well by resin,and that the adhesion strength of the treated fibres to resin increases significantly by about 5-8 times.In the paper the mechanism of the improvement of the adhesion has been discussed.The varieties of polar oxygen containing groups produced in the surface layer which form chemical bonding and the plasma etched pits spreading all over the surface of the treated fibres into which the resin penetrates to form the mechanical interlocking between fibre and resin are the two reasons for the improvement.