In this study, the multiaxial ductility factor was analyzed based on the power-law creep grain-boundary cavities growth theory under multiaxial stress states. Based on this theory, the theoretical cavities growth rates under a multiaxial stress state were discussed and the predicting model of a stress-state parameter α was revised by using an empirical fitting expression denoted as α_Wu, which exhibited a good agreement to analytical results of the stress-state parameter α and multiaxial cavities growth rates. Then, according to the re- lationship between uniaxial and multiaxial creep failure strain, a new empirical predicting model of multiaxial ductility factor MDF_Wu was established which involved the multiax- ial parameter α_Wu and uniaxial parameter α₀. Besides, the theoretical model of multiaxial ductility factor MDF could also be established. By fitting the theoretical values of MDF, an- other predicting model MDFWM was proposed. The development of two multiaxial ductility factor predicting models could be achieved. Finally, predictions of these two novel multiax- ial ductility factor models and the Cocks-Ashby as well as Wen-Tu model were compared with experimental data, and the prediction accuracy of MDF_Wu and MDF_WM models was significantly improved, especially for the latter one.