The use of natural resources in composite materials becomes more frequently, as they are low-cost and lightweight materials. In addition, industrial trends tend towards Eco-products, hence the importance of integrating natural products that are recyclable and easily degradable. Aim of this study is prepared polymer composites of polyvinyl chloride (PVC) using palm fibers at different loading (10 and 30 % by weight). Improving the interfacial adhesion between matrix-filler interfaces using chemical modification of date palm fibers (DPF) by two types of treatments (acetylation, alkali). The effect of chemical treatment and fiber content on morphological, thermal, mechanical and water absorption properties of composites have been studies. It was found that the use of treated fibers in PVC composites improves the mechanical properties and decomposition temperature, and reduce water absorption of the composites.