The characteristics of gas-liquid flow in v-type pipeline in the rolling terrain were studied by laboratory experiment. Seven flow patterns were observed in the experiment, and the fluctuation signals of liquid holdup of different flow patterns were obtained. Based on the experimental data, the discriminant effects of the improved Taitel-Dukler criterion, B?e criterion and the modified B?e criterion were verified. The experimental results show that the serious slug flow I, II and III are of obvious periodicity, and have a large power spectral density (PSD) peak, and the peak is I> II> II. The PSD amplitude of annular flow is the minimum. The angle of v-type pipeline’s angle has a significant impact on the range of serious slug flow. When the angle of downward inclined pipe or upward inclined pipe of v-type pipeline increases, the amount of liquid accumulates in the depression area at the bottom of the pipeline increases, the area of SS I increases, and the area of annular flow decreases. The calculated results of the improved Taitel-Dukler flow pattern discriminant criterion are basically consistent with the experimental data under different inclination. The airmass flow region observed experimentally is smaller than the calculated results of the criterion, while the annular flow region calculated by the criterion is larger than the experimental observation results. The modified B?e criterion is better than the B?e criterion. In this experiment, the correction coefficient of B?e criterion was 3 in the condition of large undulations.