Abstract: A new modified A-286 （15Cr-28Ni-1.5Mo-lW-2Ti-Nb-Al） （mass fraction） designated as GH871 is characterized by high strengths but low ductility at 650℃ stress rupture and also high crack propagation rates at 650℃ creep and creep/fatigue interaction conditions. For improvement of ductility and crack propagation behaviour, a primary vacuum induction melting and followed electro-slag refining process （VIM+ESR） has been adopted instead of air melting and electro-slag refining process （AIM+ESR）. Vacuum melted GH871 (VIM+ESR) can keep the high strength level of this alloy and improve the ductility and also decrease crack propagation rates by this alloy purification. It is a good combination of strengthening and toughening for the alloy improvement and development.