Abstract: Intermittent flow behavior in a vertical channel under low-pressure conditions is experimentally studied using a small scale experiment facility in the present study. The effects of different factors on the flow characteristics are investigated in detail. The results reveal that the steam eruption occurs periodically in the vertical channel. This flow pattern shows typical features, such as a time-consuming boiling delay period, and remarkable time-variation of periodicity parameters. The temperature and pressure in the flow channel fluctuates greatly accompanied by steam eruption and refill of super-cooled liquid. The flow period decreases by increasing the heat load and channel aspect ratio.