In this study, Aegle Marmelos leaves were collected from Rajgurunagar area. TheAegleMarmelos leaf extractwas prepared in deionisedwater and used for the biosynthesis of copper nanoparticles. This prepared extract added to 1mMol of copper chloride solution. The colour of the solution changes from faint blue to green colored; this confirms that there is a formation of Cu nanoparticles. The synthesized Cu nanoparticles were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) spectrumand we calculate the size of Cu nanoparticles from XRD and found 48 nm. The merits of this method are easily starting material, inexpensive and process is simple to carry and pollution free.