Dramatic advances in the development of wood plastic composites have germinated a great deal of research in the promising field. Polymer blend and composites have been studied extensively, and their properties were dependent on miscibility and structure of all components. Three or more phases in polymer blend and composite systems have increasingly attracted scientists, researchers and industries, especially, efforts to improve and modify the composite properties. Poly(vinyl chloride) (PVC) is one of the most widely used thermoplastics in packaging and construction applications. PVC products are likely to be blended by olefin polymers such as polyethylene (PE) and polypropylene (PP). PVC/PE blend has been utilized in several applications. In the present study, an attempt is made to investigate the effect of nanoclay (Cloisite 30B) in order to measure impact strength and tensile strength of Wood-polyvinyl chloride/low density polyethylene composites as well as its water absorption and thermal expansion. To achieve this aim, at first low density polyethylene (LDPE) at levels of 10,20,30,40 phr with MAPE as coupling agent were added to Wood/poly(vinyl chloride) composites. The result show that, the composite with 30phr LDPE have best impact strength and water absorption of this sample was decreased abut 1 percent rather than pvc/wood composite so this sample selected for second for second step of this study. .The micrographs of scanning electron microscopy (SEM) confirmed a good coherence existing between lingocellulosic filler and PVC/LDPE matrix. In the second step, Nanoclay at levels of 1,2,3,4 phr were added to of Wood-polyvinyl chloride/low density polyethylene composite that have 30phr LDPE. In this study samples employing a melt blending two-step process in twin screw extruder were built. While tensile and impact specimens were prepared by using compression molding method. All samples were tested in same condition and the experimental results suggested that the optimum properties could be obtained using LDPE of 30phr and Nanoclay of 3phr. Impact strength and water absorption of this compound was improved than pvc/wood composite about 8 and 61 percent.Also thermal expansion of this sample is 4/5×10 -5 . Finally, X-ray diffraction (XRD) data sample reflected that exfoliated structurex were developed in the optimum sample and other sample with lower content of Nanoclay Keywords: Wood plastic composite,PVC/Wood composite,LDPE/PVC/Wood,Cloisite30B