In the current study nanocellulose was isolated from walnut shell using mechanical and chemical methods. This study highlights the particle size, morphology and these methods’ efficiency in nano structure extraction. The difference between morphology and size of the particles (of the both extracted methods) were investigated by field emission scanning electron microscopy (FESEM). Walnut shell is an agro-waste material with source of lignin and cellulose. Ball mill-ing with different times, in the presence and absence of additive and acid hydrolysis were used as mechanical and chemical methods, respectively. The result showed mechanical method is unable to extract nanoparticle and just reshape the walnut shell. Milling time were also found important in morphology of fiber extracted. FE-SEM images represented that structure mean diameter of using ball mill was 1± 5 μm while hydrolysis acid method extract nano particle with mean diameter of 40± 20 nm.