Backround: Cancer is a sever burden and a fatal disease in the existing century and worldwide measured as a foremost health concern. Objective: The present analysis involved in evaluating the anti-tumour property of Ulva fasciata Delile in in vitro model and anti-microbial activity against pathogens. Materials and methods: The anti-cancer effectiveness of methanolic extract of Ulva fasciata has been identified at different concentrations after 24 hours of exposure of HepG2 cells using assays. Results: The seaweed extract showed a remarkable cell toxicity potential at the concentration of 100 μg/ml with superfluous ROS formation and lactate dehydrogenase and GSH enzyme release and initiating severe damage to the mitochondrial integrity of the cells. Conclusion: This investigation displayed that the methanolic extract of Ulva fasciata were more potential seaweed triggering cytotoxicity, inducing apoptosis and establishment of ROS dependent mitochondrial damage induced cytotoxicity in HepG2 cells. The sea weed extract exhibits significant anti-microbial activity against pathogenic bacteria and fungi and anti-cancer efficacy.