In this study, the effects of clay type and surface treatment on the gas permeability, mechanical properties, and processing properties of LDPE / Clay films were studied. Two types of clay, a nanotube type halloysite and a nanoplate type vermiculite, were used. The effect of clay shape and surface treatment on the dispersity of clay in composites film and the effect of stretching properties of composite film were investigated. Also, the change of physical properties of films due to the draw ratio was compared and analyzed. As a result of drawing of the composite film, it was found that stretching was impossible when the clay content exceeded 1 wt%. When the Clay surface was treated with hydrochloric acid, the elongation of the composites film was improved. These results are considered to be due to the improvement of the dispersity of clay in composites film after surface treatment. The maximum elongation ratio of 1 wt% Halloysite composites film was higher than that of vermiculite composites film. Overall, it was found that the drawability of halloysite composites film was better than that of vermiculite composite film. The effect of draw ratio on the physical properties of two types of clay composites films was compared. At draw ratio 2.0, the strength of halloysite composites film was higher than that of vermiculite composites film. The maximum draw ratio of surface treated halloysite composites films was the highest at draw ratio 4.0, and the strength was increased to about 3 times that of unstretched films. As the draw ratio increased, the gas permeability decreased, and the gas permeability did not change significantly with the difference of clay type. As the draw ratio increased, the degree of crystallinity and orientation also increased. There were found to have a linear relationship between the increase in orientation and the increase in strength.