The synthetic dye industry is a significant source of anthropogenic pollutants emitted into many water bodies across the world. Bioremoval is a substitute for industrial techniques for detoxifying dye-contaminated water. Green algae is an abundant microorganism processing to produce cost-effective, eco-friendly, and high-quality method to bioremediation by immobilization technique. In this present study, The effectiveness of the immobilized green alga Chlorella vulgaris to eliminate Congo red dye in both water and wastewater was assessed through the biodegradation Process under various conditions, including pH, concentration of dye, contact time, and NaCl. The results revealed that the removal increased with increasing contact duration, with the maximum bioremoval percentage occurring at 89.6% at a contact time of 13 days. The removal effectiveness of dye as the number of beads of immobilized C.vulgaris algae grew; the highest removal efficiency was achieved at 7-8 beads of immobilized C.vulgaris algae. There was also an inverse relationship between bioremoval and dye concentration; the maximum removal percentage was 90.1% at 0.1 M dye concentration. The highest removal efficiency was found in the range (91.3–86) at pH 6-7. The bioremoval of Congo red dye was similar in fresh and salinity water (87.2% and 85.3%, respectively). This study observed high removal efficiency for immobilized algae to Congo red under different concentrations of NaCl as an indicator of salinity, ranging between 85.3 and 87.2%.