Nanotechnology is considered one of the most frontiers in scientific sector, which increasingly attracted researchers' interest due to its variable and valuable applications in all areas. Recently, green nanotechnology is serving as an important technique that making the processing more friendly, safe and clean. Selenium is one of the most important dietary supplements in the human diet. It is incorporated into the synthesis of many antioxidant enzymes. Therefore, selenium has become antagonistic to many diseases relying on oxidative stress such as cancer, brain and heart illness. In this study, biogenic selenium nanoparticles (Bio-SeNPs) physicochemical characteristics such as formation, morphology and biological activity of Bio-SeNPs as antimicrobial, antioxidant and anticancer were investigated. Transmission electron microscopy (TEM) micrograph of biosynthesized Bio-SeNPs by Fusarium sp. showed an average length of 61.18 ± 15.85. Antioxidant activity in vitro had showed higher (2,2'-azino-bis(3-rthylbenzothiozoline-6-sulforic acid) ABTS radical scavenging ability and powerful antioxidant potential (5.656 ±0.12 mmol trolox/g) than (1,1-diphenyl-2-picrylhydrazyl) DPPH (1.362 ± 0.09 mmol trolox/g) as well as Bio-SeNPs possess potent antibacterial potential against burns wound infections and selective anticancer potentials against colon, skin and lung cancers without effect on human normal cells. These findings demonstrate the positive effects of Bio-SeNPs as a promising candidate for future therapeutic applications.