Research on making films using chitosan, nanocellulose from pineapple leaf fiber, and glutaraldehyde were carried out as an effort to obtain alternative biodegradable plastics. Chitosan has low mechanical, therefore nanocellulose is added from pineapple leaf fibers and glutaraldehyde additives. This research was conducted to obtain the optimum glutaraldehyde additive variable that functions as a crosslinker. What chitosan used was 2% (w/v solution) and nanocellulose 3% (w/w chitosan) based on optimum results from previous research. The method used a casting method, chitosan and nanocellulose are dissolved and heated in acetic acid 1% then glutaraldehyde is added during cold and cast. Variable of glutaraldehyde added by 0%, 0.5%, 1%, 2%, and 3% (w/w chitosan). Tensile strength, elongation, functional groups, and absorbance were used to characterize film. The results showed that the results of FT-IR were a spectrum of chitosan and indicated the crosslinking between chitosan and glutaraldehyde. The tensile strength values change with the addition of glutaraldehyde. The optimum value of adding glutaraldehyde is 1% based on the results of tensile strength and the lowest absorbance.