With the analysis of the multiaxial fatigue behavior of the thin wall specimens and notched specimens of GH4169 alloy as well as the state of the stress-strain by using the Finite Element Method (FEM), a new damage parameter for multi-axial fatigue is proposed by means of von-Mises criterion based on the critical plane approach. In the new damage parameter, the triaxial factor is introduced. For the new damage parameter, the maximum shear strain and normal strain on the critical plane are taken into account, and the effect of stress state under the multiaxial cyclic loading condition on the fatigue life is taken into account as well. This parameter without containing empirical constants is easy and convenient for engineering application. By combining the proposed damage parameter with the Manson-Coffin equation, the fatigue life prediction model is established. And the experimental verifications show that the new fatigue life prediction model is more accurate in predicting the high temperature multiaxial fatigue life of the thin wall specimens and the notched specimens.