By taking the circumference liquid films of cross-sectional pipe in gas-liquid two-phase annular flow for measuring objectives, a novel visual sensor with virtual two-visual angles was designed and optimized by combining a single high-speed camera and planar reflectors. Based on the virtual binocular stereo vision principle, a measurement model for visual sensor with two-visual angles was established. To maximize the effective measurement angle and to obtain much liquid film flow informations, the model of the virtual double-view vision sensor was analyzed and its structure parameters were optimized by considering the field of view, sensor size, measuring distance and the optical path refraction of the pipe. The theory analyzing and experimental results indicate that the optimized sensor can get a view field closed to 300° effective circumference visual angle, which is far better than that using a single high-speed camera to capture directly. It provides a theoretical basis for the real-time measurement of the gas-liquid two-phase annular flow circumference liquid films through the double-view vision sensor, and has great significance to study the film thickness and analyze the flow state of the annular flow.