Abstract: To make full use of the energy of gas layers to increase the daily production of oil wells and recover the flowing capacity of oil wells, the gas in gas caps or gas layers is injected into the production wellbore by means of the choke and pressure drop effect of inflow control device, so as to decrease the density of the fluid in the wellbore and extend the flowing period of oil wells. In this paper, the flow theory of automatic gas lift system was analyzed comprehensively, and the effects of sensitive factors (e.g. water cut of the oil reservoir) on the depth of gas injection points were investigated using the software PIPESIM. Besides, the area of control device under different openings was designed by means of the nodal analysis method. It is verified by the case simulation that the production rate of oil well is increased by 2.4 times from 120 m³/d to 413 m³/d.