A rapid optical inspection system for rapid measuring the surface roughness of titanium dioxide (TiO2) thin films is developed in this work. The incident angle of 60° is a good candidate for measuring surface roughness of TiO2 thin films and y = 90.391x + 0.5123 is a trend equation for predicting the surface roughness of TiO2 thin films. Roughness average (Ra) of TiO2 thin films (y) can be directly deduced from the peak power density (x) using the optical inspection system developed. The results were verified by white-light interferometer. The best measurement error rate of the optical inspection system developed can be controlled about 8.8%.The saving in inspection time of the surface roughness of TiO2 thin films is up to 83%.