Void fraction as one of the basic parameters of gas-liquid two-phase flow is of great significance to the development and transportation of petroleum pipelines and the design of nuclear reactor cooling towers. This paper proposes a direct detection method of void fraction based on laser-induced fluorescence imaging technology and high-speed video recording system, which can effectively avoid optical distortion caused by pipe curvature and refractive index of the medium. Experiments were carried out on the multiphase flow circulation device of Hebei University, and 18 flow points were measured. The liquid flow measurement range is 10~ 35 L/ min and the gas flow measurement range is 2. 0~ 3. 0 L/ min. Using the idea of measurement comparison, the deviation of the void fractions obtained with two detection technologies is calculated and corrected, and the maximum deviation is only 0. 014 59. The results show that the void fraction values obtained with the two methods are in good agreement, which proves that the fluorescence imaging technology proposed in this paper is effective for the detection of gas-liquid two-phase stratified flow void fraction.