Abstract: In October 1998 and July 2003,pilot testing and exten-ding testing of 11 well groups of Qi 40 block was carried out. At present,it is in the erosion stage for late develop-ment of steam stimulation. In order to maximize economic efficiency,by using numerical simulation,the research on intermittent steam injection has been carried out. In the end,the parameters such as the manners,time and steam injec-tion speed of intermittent steam injection has been designed. Obvious effect has been achieved after application on well site: the oil-gas ration increases from 0. 14 to 0. 20,which provides guidance for reasonable adjustment of steam stimu-lation in late stage.