Aiming at the bad stability performance of normal foam in the Yan Chang No.6 oil field, a high stability gel foam system was developed and then evaluated in the aspect of stability and plugging. Through comparison and selection, now the system is made up of 0.4% FP388 foam agent, 0.3% AZ polymer, 0.3% T1&T2 crosslinker, and 0.3% CK2 foam stabilizer. The stability experiment of gel foam indicate that the half life of gel foam is 12 d and the viscosity of gel foam can stay at a high level, also remains stable in 30 d under 80 ℃ and 10 000 mg/L mineralization degree environmental conditions. The foam gel system has good injection and gel forming properties and can effectively seal medium high permeability reservoir.