Over the past few years, nanoparticles (NPs) have found diverse applications across various scientific and technological domains, ranging from material science to biotechnology. Consequently, the synthesis of NPs has emerged as a vibrant field of research. However, traditionally integrated NPs have exhibited a non-toxic nature, prompting the need for further exploration. Then green synthesis is involved as primary objective to minimize the reliance on toxic chemicals. An example of this is the utilization of biological materials, such as plants, which generally offer a safe alternative. This study deals with the green synthesis of cadmium Oxide nanoparticles (Cdo NPs) with its characterization for biomedical applications using plant extract as a reducing agent and covering. Calendula officinalis plant is used as plant extract for the green preparation of CdO NPs. a variety of characterization methods such as Ultra-Violet spectroscopy (UV), Infrared spectroscopy (IR) and Scanning Electron Microscope (SEM) have been used to classify the composite nanoparticles. Agar well diffusion was employed to evaluate the antibacterial activity of nanoparticles synthesized through a green approach. Through this study it was illustrate that the utilization of plant extracts in nanoparticle synthesis through green synthesis technology ensures a biologically safe, advantageous, and environmentally friendly approach.