A seasonal taxonomic study was conducted of Attached Cyanophyceae algae on biological treatment pond in Dura refinery at Baghdad city for three seasons (Summer, Autum 2020, Winter 2021). The current study recorded (41 species) belonging to (13 Genus) of attached Cyanophyceae algae, including three Orders: Oscillatoriales were the dominant group (4genus, 16 species), followed by Chroococcales (5 genus, 15 species), and Nostocales (4 genus, 10 species). Cyanophyceae are characterized by ability to live, grow and reproduce in a wide range of environmental changes and pollution levels especially industrial waste. Cyanophyceae can be revived in the pond as it has the ability to break down petroleum and organic compounds.