This paper is based on the working principle of the array ultrasonic sensor and the principle of the array ultrasonic sensor in the measurement of the gas-liquid two-phase flow section holdup. An image reconstruction of the pipeline section is derived through the coordinate transformation of the data matrix points. Based on the image characteristics, the average section gas holdup measurement model of three flow patterns is proposed. The volumetric gas holdup was established by using the section gas holdup obtained by the model. Compared to the real volume gas holdup, the absolute error was within ±11%, indicating that the model is of high accuracy.