Abstract: To promote photo-stability of cotton fiber and protect it,nano-hydroxyapatite(HAP) was used to finish the cotton fabrics functionally.According to the results of contract SEM and IR experiments,the article analyzed the process of combining cotton fiber with nano-hydroxyapatite,selected the optimum conditions: nano-hydroxyapatite was dispersed in water and adjusted pH to 12.30 with ammonia,it could be distributed on cotton fiber evenly and compactly.The experiments turned out that the finished cotton fabrics with HAP had good protection effect in TiO2photocatalysis,and its bursting strength was 24.51% higher than that without nano-hydroxyapatite at the same condition of UV damage.