The present work describes design and preparation of novel PVA nanocomposite films using CuO NTs and Asp by solution casting method. The required CuO NTs prepared by novel biogenic method using Robinia Pseudoacacia Leaf Extract. The prepared CuO NTs and nanocomposite films are characterized by various spectroscopy techniques. The adsorption and photocatalytic efficiencies of PVA nanocomposite films were compared with pristine CuO NTs. The adsorption capacity of PVA nanocomposite films showed higher due to functional groups, presence of active sites, high surface activity and semiconducting nature of CuO NTs and Asp embedded in PVA matrix. The adsorption behavior of the nanocomposite shows that adsorption isotherms and kinetics are in good agreement with Langmuir equation, Freundlich equation and pseudo-second-order, respectively. The comparative photocatalytic activities of the CuO NTs other nanocomposite films are examined methylene blue (MB) as a substrate degradation, and film PVA/CuO NTs/Asp showed highest (up to 77%) degradation compared to other films and CuO NTs in 50 min time duration. The improved photocatalytic behavior of PVA nanocomposite film attributed to its narrower band gap reduces the recombination rate of exited electron-hole, enhanced UV-Vis absorption intensity, improved utilization of sunlight and enhanced adsorption of dye due to functional groups, surface wettability, hydrophilic surface and self-cleaning nature.