Aiming at the aging deformation of turbine blades in turbine engines under complex stress, Waspaloy nickel-based alloy was taken as the research object to carry out aging treatment and complete quasi-static high temperature mechanical tensile tests of Waspaloy nickel-based alloy at 600, 700 and 750 ℃. The flow stress of Waspaloy nickel-based alloy at high temperature plastic section was predicted by Ludwik and Hollomon empirical formulas, and the mean error (E_r) and root mean square error (RMSE) were introduced to evaluate the accuracy of the flow stress prediction. The results show that the hardness of Waspaloy nickel-based alloy is improved effectively after aging treatment, but its plastic properties are reduced. The tensile strength and elongation of Waspaloy nickel-based alloy are negatively correlated with the loading temperature in the range of 600 ~ 750 ℃. Ludwik model owns higher accuracy than Hollomon model in flow stress prediction, but there is a still large error in flow stress prediction in high temperature and high strain region. Based on the Ludwik model, the exponential term is introduced, and the modified Ludwik model have a better prediction result in the flow stress of Waspaloy nickel-based alloy at high temperature plastic section.