Abstract: In October 1998,steam drive pilot of 4 well groups are carried out in Lian Ⅱ layer of Qi-40 block.Steam drive expansive experiments of 7 well groups are carried out in July 2003.There are 11 well groups in steam drive area of Qi-40 block at present,which are all at the late development stage of steam drive breakthrough.Numerical simula-tion is applied to the late development stage of thermal recovery technology after water flooding to improve the eco-nomic efficiency of steam drive and to provide the adjustment of technology options for industrializing area.Injection temperature,injection rate and other parameters are designed to field show obvious effect.Oil-steam ratio climbed from 0.13 to 0.15,which provide a reasonable adjustment model for steam drive in late development stage of steam flooding.