Green composite become very considerable in the new investigations and research because of its potential in replacing polymers and metals in some industrial applications. Replacing polymer parts with green composite in vehicle's interior parts is important application. In this study, the stiffening efficiency of long flax yarns -made of short discrete fibers- is investigated to reinforce polyester laminate. Single-layer (lamina) ,samples made of polyester matrix and reinforced with unidirectional flax-yarn textile (UFRP), was investigated in this study. In order to examine the manufacturing process effect, both hand layup and compression molding techniques -at different packing pressure- were used to produce different UFRP laminae. Tension and flexure testes were applied to measure the main mechanical properties of different produced UFRP laminae. In addition, two main fiber's directions (00 and 450) were considered during testing to investigate the fiber's orientation's effect. Microscopic images showed good fibers distribution and resin-fibers impregnation across hand layup and compressed UFRP laminae, while testing approved the remarkable advantage of using flax –yarn textile to remarkably enhancing the mechanical performance (e.g. tensile strength, stiffness, toughness and ductility) of plain polyester sheet.