Due to versatile use, the demand of plastic and plastic made products are increasing tremendously which leads to create pressure on petroleum resources. Thus, boosting up the utilization of recycled plastic is necessary. Although, a number of researches have been carried out with natural fibre reinforced polymer composites, however, fibres are not compatible with most thermoplastics due to their hydrophilic nature whereas; plastics are mostly hydrophobic in nature. Surface modifications of fibres to improve adhesion and mechanical properties of composites are drawing attention to the researchers widely. Ultrasound can be used as green chemistry technique to treat the fibre to remove the lignin for the better adhesion between fibre and polymer matrix. Tremendous effect of ultrasound led to removal of lignin result in better mechanical properties of the composite, which can be used as vehicle body parts. The researchers of polymer composite can find useful information in this article.