Abstract: Based on the results of therm- recovery numerical simulation, this paper presents analyses of geological , steam injection and completion parameters affecting steam injection development of the IXs pilot project in Karamay oilfields.The results illustrate that major geological parameters affecting the efficiency of steam injection development are effective thickness of the pay and crude viscosity. Effect of the absolute permeability manifests mainly in the early period with a little effect on the ultimate recovery. Highly permeable zone and permeability anisotropy existing in the pay zone display certain effects on the steam injection recovery. After steam breakthrough in producing wells, decreasing steam speed into injection wells improves efficiency of the recovery.