In this paper, the elastic modulus of nanocellulose/PLA nanocomposites obtained by the two methods including nanoindentation and tensile tests were analyzed. Nanocellulose extracted by Mechanical method from linter pulp fiber. Amount of usage of nanocellulose was 3 and 5% wt , as well as for improving of nanoparticles distribution in polymer matrix, masterbatch technique was used. Then the mechanical properties of nanocomposites with and without this technique were studied. Tensile test was performed in accordance with the standard method and for nanoindentation, the atomic force microscope in peak force tapping mode was used. Tensile test results showed that the use of masterbatch, improves tensile modulus, tensile strength and strain at break. Also by increasing nanocellulose percentage from 3 to 5%, in nanocomposite with master batch, the tensile strength and strain at break increased. But this increasing had not significant effect on tensile properties of nanocomposite without masterbatch. A similar trend of strength test results was observed in nanoindentation results. Based on this result, using of masterbatch in nanocomposite caused the increase in elastic modulus. The results of these two analyses were compared and tensile test showed lower modulus value than nanoindentation.