The demands for polymeric materials with a unique combination of properties are ever growing. A cost efficient solution to meet the demands is the use of polymer blends. By blending different polymers, new materials with a desirable combination of properties can be developed. Engineering plastics are blended with polyolefins in order to improve the performance of them (rigidity, thermal stability, mechanical and barrier properties to oxygen and solvents). Besides mixing different polymers, organomodified clay has been added to polymers to form nanocomposite polymers and attain better properties. Recently, several research groups have tried to use simultaneously the two previous approaches in order to produce nanocomposite polymer blends with improved performances. The relationship between morphology and properties of nanocomposite blends is very important for designing new materials. In this work, the relationship between morphology and mechanical and barrier properties of LDPE/LLDPE/PA6/nanoclay nanocomposite films was studied. At first, the impact of feeding order of compatibilizer on the morphology and mechanical properties of the films was investigated. Then, the effect of type (cloisite 15A, cloisite 30B) and concentration of nanoclay(3,4,5 phr) was studied. Finally, the effect of temperature on film processing, morphology, and properties was investigated. The blends were prepared by melt mixing of component, using a co-rotating twin-screw extruder, and then melt-drawn in to films by casting method. The composition of the PE/PA6 was 70/30 wt; in all cases, a mixture of LDPE/LLDPE with weight ratio of 70/30, a common ratio in the film industry, was used as the PE matrix. The nanocomposites blends were characterized by means of FTIR, X-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FE-SEM). Final properties of the produced films were investigated using tensile test (TS), and Oxygen Transmission Rate (OTR). In situ compatibilization of components in PE/PA/PEgMA blends performed better in simultaneous mixing. This can be generally attributed to the production of more graft copolymer at interface, which enhanced the adhesion between the polymer phases. The results showed that the nanocomposite structure depended on the type of nanoclay and the presence of a compatibilizer. The presence of the Cloisite 30B promoted the formation of a co-continuous morphology for the LDPE/LLDPE/PA6 blends. As the concentration of this nanoclay was increased up to 4 and 5 phr, the co-continuous morphology was formed and their tensile modulus was also enhanced as much as 19.43% and 30.36%, respectively. Oxygen transmission rate was declined around 37.58% for nanocomposites with 4 phr Cloisite 30B and 45.47% for 5 phr Cloisite 30B. Moreover, improved morphology and better properties were attributed to the decrease of temperature profile in film processing. The mechanical properties were increased (3.9% increase in modulus, 12.83% increase in tensile strength and 24.21% decrease in elongation at break) and oxygen transmission rate was decreased to about 7.22%. By comparing the morphology of samples after mixing and also after film processing, it was found that the Orientation of PA6 particles was occurred in film processing, leading to the improved morphology. Keywords: nanocomposite, blends, co-continuouse, mechanical properties, barrier