Abstract: The edge water cusping is serious during the steam stimulation of Henan oilfield because of the existence of edge water in the heavy oil reservoir,and the well water cut increases sharply for the edge water cusping.An experimental device which could simulate edge water was designed according to the feature of Henan heavy oil reservoir with edge water,and the effect factors and application conditions of nitrogen foam anti- edge water- cusping technology for steam stimulated well was studied with the device.The results show that the anti- edge water- cusping technology fits for the heterogeneous reservoir with a moderate energy edge water,and a better blocking result will be achieved if the technology is applied at the time of serious flooding.Field tests were proceed on the basis of experiment results and field experience,and the success rate was 100%.The average drainage period decreased by 0.7d,the average water cut decreased by 23%,and the oil/steam ratio increased by 0.25.The technology reduces water cut and increases oil production significantly,so the target of edge water inhibition is achieved.