Abstract: A three-dimensional physical simulation on steam flooding of ultra-heavy oil reservoirs for an inverted nine-spot well network was designed according to reservoir conditions of the Shan-56 block in the Shengli oilfield and conducted under conditions of the 20%, 40% and 60% steam dryness respectively, in order to analyze the production status of a single well or well group and improve recovery effects of ultra-heavy oil reservoirs by nitrogen foam injection on the basis of steam flooding. The experimental results show that the steam channeling of ultra-heavy oil reservoirs is relatively severe, the comprehensive water cut rises fast and steam chambers develop unevenly. Edge wells have an increase in production, while corner wells show a poor temperature growth and low level both liquid and crude production, thus contributing a little to the well group output. The steam flooding recovery could be enhanced remarkably by increasing the steam dryness, for instance, the displacement efficiency of steam flooding increased by 19.86% when the dryness of injected steam rose from 20% to 60%. When slug injection was a 0.093 PV foam system on the basis of steam flooding, the steam channeling could be effectively suppressed along with a remarkable decrease in both the liquid production and comprehensive water cut of edge wells. Moreover, a temperature field around corner wells began to develop along with a significant increase in both the liquid and crude production, the comprehensive water cut of intervals decreased by 7%, while the recovery ratio was enhanced by over 15%. Therefore, the enhanced oil recovery of ultra-heavy oil reservoirs can be further increased by increasing the steam dryness in steam flooding associated with an auxiliary profile control technique, nitrogen foam injection.