This study investigates using the phytoremediation method to treat textile wastewater by analyzing COD reduction. The study uses the plant species Rhizophora mucronata in a designed treatment tank. Over 45 days, the COD of the wastewater was analyzed at 15 day intervals. The results showed a 15% reduction in COD after 15 days, 45% reduction after 30 days, and an 87% reduction after 45 days, demonstrating the effectiveness of using Rhizophora mucronata to treat textile wastewater through phytoremediation.