Abstract: The cotton indigo denim was treated by using ecological laser washing technology. The surface composition before and after washing was analyzed by using infrared spectrometer, and the tensile strength,air permeability, abrasive resistance, thickness and K/S values (dyeing deepness) of denim fabric were tested.The results showed that the washing effect was very distinctive when laser power ranging from 75% to 85% and working speed ranging from 10 000 to 12 000 mm/min. After washing, no new substance was formed on the surface of denim, the tensile strength, air permeability and K/S values of the fabric declined by different degrees, the abrasive resistance and thickness did not change significantly. Compared with traditional washing methods, laser washing is more environmental-friendly and it effectively reduces the processing costs and is in line with the concept of green production.

Key words: cotton indigo denim; ecological laser washing; environmental protection; tensile strength