Recently, a novel 718 superalloy with remarkable structural stability at 680°C has been designed and fabricated by CISRI (Central Iron and Steel Research Institute) etc. Phase identification of novel 718 alloy under the above-mentioned heat-treatment condition was performed using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results show that the novel 718 alloy has outstanding structural stability at 680°C. The novel 718 alloy possess excellent structural stability and good mechanical properties, which is attributed to γ-phase strengthening and also to the specific sandwich structure of the γ′ + γ″ strengthening phase.