The slug flow is a common flow pattern in the multiphase flow. The accurate measurement of flow parameter phase fraction is the prerequisite for analyzing the flow state and obtaining the average density of the mixture. It is of great significance to the fields of petroleum and chemical industry. First, according to Fresnel′s law and Maxwell′s equation theory, the distribution characteristics of light on the pipe arc is derived. A single-shot and multiple-receiving near-infrared sensor is designed to study the propagation characteristics of near-infrared spectrum in slug flow. Experiments prove that the voltage value received by each probe on the circumference of the pipeline is cosine with the installation angle of the probe. According to Lambert-Beer law, the relationship among the voltage value received by the near-infrared probe, the installation angle of the near-infrared receiving probe and the phase fraction deduced is achieved. The phase fraction measurement model of the slug flow is formulated. The experiments are implemented in a horizontal transparent pipe with an inner diameter of 50 mm, the gas flow range is between 0. 5 m 3 / h and 2 m 3 / h, and the liquid flow rate is between 5 m 3 / h and 9 m 3 / h. Research results show that the relative error of the prediction model of phase fraction is within ±7% .