Chemically modified bacteriorhodopsin (BR) films embedded in gelatin matrix were fabricated. It was found that chemically modified BR/gelatin film remained the original conformation of BR and possessed homogeneity. Then, the photochemical conversion from all- trans O state to 9- cis P state in the chemically modified BR film/gelatin was investigated. For comparison purpose, the same conversion in the wild-type BR (BR wt) film was also presented here. To our know, it is the first report to show that the absorption changes of the P state in the chemically modified BR film were larger than in the BR wt film upon illumination with red light at the low actinic power density.