In order to increase the response sensitivity of detector and reduce the loss of light energy when a broad spectrum beam is incident, a kind of optical film is developed, which can realize anti-reflective at a broadband between ultraviolet-c and near infrared. Based on the anti-reflective thin film theory, combined with tunneling and automatic optimization, an evaluation function is established by comprehensively considering the factor effect of film thickness. By optimizing the deposition process, the transmittance of the anti-reflective coating is improved. The results of spectral tests show that the average transmittance in the bands of 200 nm to 900 nm is 95.7%, which satisfies the requirement of spectroscopy detection.