Recently, the use of natural fibers as reinforcing agents or fillers in thermoplastic polymer matrices has been of much concern to researchers because they are renewable, environmentally friendly and abundant in nature. In addition to the benefits provided by natural fibers, the strong polar nature of the surface causes its use as a reinforcement in the thermoplastic non-polar matrix to be limited. This problem can be overcome by surface treatment methods that aim to change the polar properties of natural fibers to be non-polar, so that the compatibility of natural-thermoplastic polymer fibers becomes better. In this study, the method of natural fiber treatment, namely bleaching-hydrolysis and TEMPO treatment was applied to Dendrocalumus Asper fibers (betung bamboo). The effect of chemical treatment on crystallinity index was evaluated by XRD instruments. FE-SEM and FTIR were used to describe the morphology and chemical composition of treated and untreated fibers. Based on the results of the data obtained from the experiment, it was shown that the fibers undergoing bleaching-hydrolysis treatment produced better crystallinity index properties than TEMPO treatment and untreated fibers.