Nowadays, the issue of packaging and quality improvement of packaging products as well as the use of environmentally friendly packaging materials has been considered by many food-related industries and researchers. In recent years, special attention has been paid to biopolymers such as polylactic acid and its derivatives as the coatings materials used in the food industrial packaging, especially for raw foods packaging. Its replacement with common used materials such as glass, metal, paper and plastic is significant. In this study, a polylactic acid polymer film was prepared which was used as a nanocomposite substrate. Also, extracted shrimp shell nanofibers were used as the enhancer and filler of the prepared nanocomposite structure. In this research, chitin fibers were chemically extracted from shrimp shells and then, through a mechanical process, the extracted fibers were converted into nanofibers. Also, polyethylene glycol usage as a softener in the nanocomposites preparation, improved the strain at the rupture point. Various mechanical tests such as water absorption, oxygen transfer rate, water vapor transfer rate, light transmission and color measurement were performed to evaluate the effect of extracted shrimp shell chitin nanofibers and polyethylene glycol softener on the prepared nanocomposite and these mechanical tests results were analyzed. Also, nanofibers used in this study were evaluated and characterized by FTIR, FE-SEM and XRD techniques. According to the results, chitin nanofibers addition to polylactic acid films improved the mechanical and barrier properties of the nanocomposite, but the addition of polyethylene glycol softener did not have a favorable effect on the nanocomposite inhibition properties due to its characteristics. However, some prepared nanocomposite properties, such as biocompatibility and biodegradability, its economics and high efficiency have led its use in the packaging industry. Keywords: Biodegradable Polymer, Biocomposite Film, Shrimp Shell, Chitin Nanofibers, Polylactic Acid