The fracture-cavity reservoirs in Tahe Oilfield are faced with prominent problems，such as unidirectional effects and gas channeling after nitrogen flooding. In order to effectively control gas channeling and expand the swept volume，a new reinforced foam system with high temperature resistance and high salt tolerance，namely a dual-crosslinked high polymer gel foam system is developed. In addition，reinforced foam with nitrogen flooding flooding tests are carried out in the eastern old area of Tahe Oilfield.Laboratory experiments and field tests show that the new reinforced foam system is synthesized by 0.3% mass concentration of anionic-nonionic/anionic composite synergistic foaming system and 0.7% mass concentration of polymer gel foam-stabilizing system.The aggregations of gel macromolecules undergo a secondary cross-linking on the liquid film of the foam，forming a dual-crosslinked high polymer gel foam system. The reinforced foam system can be strongly stable under the reservoir conditions with a temperature of 140 °C，a salinity of 240 g/L，and an oil saturation of 50%. It is suitable for the geological conditions of fracture-cavity reservoirs in Tahe Oilfield. The reinforced foam test with nitrogen flooding is carried out in 10 wells in Tahe Oilfield. Specifically，gas channeling is effectively controlled，and the swept volume is expanded in nine wells，with the production increasing significantly. Therefore，it is proved that the reinforced foam with nitrogen flooding technology is a feasible way to enhance oil recovery of fracture cavity reservoirs.