Background and Aim: Physical and chemical methods of synthesizing metal nanoparticles have been the focus for the last decade as researchers have broadly exploited them. These methods produce harmful by products. The biological synthesis of metal nanoparticles was found to be easy and economical. Green synthesis is a significant tool for reducing the destructive effects associated with the traditional methods for nanoparticle synthesis. The present work focuses on an eco-friendly approach for the green synthesis of titanium dioxide nanoparticles based on Alternanthera philoxeroides plant extract. Objective: The advantages of the green synthesis method include biocompatibility, cost-effectiveness, sustainable practices, nontoxic, environmentally benign precursors, and simple procedures with time-saving. Material and Method: Titanium dioxide, sterile distilled water, What’s man filter paper No. 1, and Alternanthera philoxeroides. The green synthesis of titanium dioxide nanoparticles is carried out in simple steps. The extract of Alternanthera philoxeroides was used for the biological synthesis of the titanium dioxide nanoparticles. Nanoparticles were characterized by UV-vis spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD). Results: The UV-Vis spectral pattern established the colloidal APTiO2NP. The surface plasmon resonance (SPR) of APTiO2NP showed maximum absorption at 372.8nm, and its energy bandgap of APTiO2NP was calculated to be 3.326 eV. FTIR spectrum confirmed the involvement of Protein, Tannins, Saponins, Phenols, flavonoids, Glycosides, and Terpenoids, which are present in Alternanthera philoxeroides that would act as capping agents for TiO2 NPs. The XRD result confirmed that the products were highly crystalline. The prominent peak was shown at 25.58°, and some other peak positions characterize the anatase phase of TiO 2NPs.   Conclusion: The synthesized APTiO2NP could be used for environmental remediation regarding antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.