Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis strain (AS1.439) from Ming lake were decomposed by photocatalytic nanostructure N-TiO(2) thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO(2) thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 degrees C (films A) or 350 degrees C (films B) for 1 h in a muffle furnace. The results showed that N-TiO(2) thin film B (8.18 nm thickness, 2.760 nm height and 25.15 nm diameter) has more uniform granular nanostructure and thinner flat texture than N-TiO(2) thin film A (12.17 nm thickness, 3.578 nm height and 27.50 nm diameter). The bactericidal action of N-TiO(2) thin film A and film B for Pseudomonas aeruginosa strain (AS1.50) and Bacillus subtilis varniger strain (AS1.439) were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain (AS1.50) and 75% for Bacillus subtilis strain (AS1.439) were achieved by using N-TiO(2) thin films-B for 70-80 min of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO(2) thin films probably depended on the characteristics of the films.