With the further exploitation of heavy oil reservoirs, steam breakthrough blocks are seen in more and more areas and pose increasing damage. Based on the qualitative understanding of the formation mechanism of steam channeling, the concepts of steaming time and heat invading volume are introduced. After that, the geological models of steam injection of heavy oil reservoirs are established. We describe the sensitive factors affecting the steam channeling in a relatively accurate manner and mainly study the influence of several parameters on steaming time and heat invading volume. The results present that the possibility of steam channeling is higher and the time it takes is shorter when the permeability is greater, viscosity higher, depth shallower, steaming strength bigger and layer looser. Orthogonal design results show that the k-values of permeability on steaming time and heat invading volume are 7.43, 19.0 respectively, it has the most significant influence on two indicators.