Microalgae　play　a　critical　role　as　a　sustainable　and　abundant　source　of　natural　antioxidant　compounds,　leading　to　a　potential　market　for　microalgae-based　food　or　feed　supplements.　Currently,　this　market　development　is　limited　by　high　cost　of　biomass　production　due　to　the　large　quantities　of　water　and　nutrients　required　for　microalgae　cultivation.　It　has　been　demonstrated　that　this　barrier　could　be　overcome　by　microalgae　cultivated　in　wastewater　containing　nutrients.　However,　there　is　a　pressing　need　to　investigate　how　the　wastewater　medium　influences　antioxidant　characteristics　of　microalgae.　This　study　examined　the　antioxidant　effects　of　wastewater-cultivated　microalgae　Chlorella　sorokiniana　(C.　sorokiniana)　using　Drosophila　melanogaster　(fruit　fly)　as　the　animal　model.　Characteristics　representing　antioxidant　properties　such　as　fly　lifespan,　behavioral　activities　and　stress　resistance　capacities,　together　with　the　potential　underlying　antioxidant　mechanism　were　assessed.　Results　showed　that　flies　fed　on　4　mg/mL　wastewater-cultivated　C.　sorokiniana　had　significantly　extended　median　lifespan　(55　days　vs　49　days　for　control),　and　improved　locomotor　activity　with　increased　step　size　and　longer　travel　distance,　although　no　significant　differences　in　struggling　activity　was　observed.　Moreover,　C.　sorokiniana　diet　provided　flies　with　protective　responses　to　both　H2O2-induced　oxidative　stress　and　anoxia-induced　disturbance　on　brain　ion　homeostasis.　These　aforementioned　effects　were　associated　with　the　mRNA　up-regulation　of　endogenous　stress-defense　genes　such　as　Cu/Zn-superoxide　dismutase　(SOD1)　and　catalase　(CAT)　as　well　as　the　down-regulation　of　Methuselah　(MTH)　gene.　Finally,　flies　fed　on　C.　sorokiniana　demonstrated　similar　feeding　behavior　and　boundary　preference,　suggesting　that　C.　sorokiniana　supplementation　did　not　cause　starvation.　This　study　demonstrated　that　C.　sorokiniana　grown　on　wastewater　still　maintained　antioxidant　properties　in　fruit　fly,　further　providing　new　insights　into　the　feasibility　of　wastewater-grown　microalgae　as　a　natural　antioxidant　alternative.