In this study, an attempt was made to investigate the properties of bacterial cellulose/polyethylene glycol (BC/PEG) nanocomposite as Bio-based Synthetic Leather, produced via two processing methods: ambient temperature treatment and curing process. The results indicated that PEG can effectively penetrate and stabilize within the BC nanofiber network, leading to the formation of a homogeneous composite structure. FTIR analysis confirmed that the incorporation of PEG induces stronger interactions and the formation of strong physical interactions and intermolecular hydrogen bonds within the nanocomposite structure . Furthermore, the fabricated nanocomposites exhibited greater thickness, flexibility, and mechanical strength compared to pure BC. Moreover, the curing process resulted in a reduction in the nanocomposite strength and an increase in elongation at break, in contrast to the samples treated at ambient temperature. It was also found that the produced nanocomposites showed enhanced thickness, flexibility, and strength relative to pure BC, such that the tensile strength of the sample containing 20% PEG (treated at ambient temperature) reached 5.22 MPa, which is approximately three times higher than that of pure BC (1.6 MPa). Ultimately, the sample treated with 20% PEG at ambient temperature, owing to its outstanding strength and flexibility, was introduced as the optimal specimen for Bio-based Synthetic Leather applications.