Abstract: In view of the water-producing gas wells in Jingbian Gasfield, the widely used technique is foam-assisted drainage supplemented with defoaming process at present. The traditional drainage methods include manual injection, injection by mobile chemical truck, pumping inside gas gathering stations, etc. In the context of gasfield development with scattered well locations and large number of gas wells, the problems like large amount of manual operation, high costs, high safety risk, contamination and untimely injection which will affect normal production are outstanding. So in order to effectively address the problem of foamer and defoamer injection on site, an automatic wellhead injection device for foamer and defoamer was developed and was tested on site at a number of gas wells. This device uses solar energy and wind energy, has sufficient power and is environment-friendly and contamination-free; it can inject foamer and defoamer timely, quantitatively and continuously, improve drainage efficiency, reduce labor costs and also avoid safety risk in manual operations; it can inject both foamer and defoamer, hence eliminating the effect of defoamed produced water on the downstream equipment; its injection technology can satisfy the requirement of gas recovery by foam drainage in gas fields, expand the application of foam-assisted drainage process and provide technical support for proper development of water-producing gas wells of gas fields in mid-later stages.