Abstract: The intermetallic phase characterization and its evolution were summarized on the most promising candidate superalloy for 700℃ advance ultra-supercritical superheater and reheater（including Inconel 740/740 H, CCA 617, Nomonic 263, Haynes 230 and GH2984, etc）. The results show that in order to meet high temperature property, most of the alloys are strengthened by precipitation, thus there are some kinds of precipitates such as γ’、η、σ、μ, G. The phase morphology, amount, size and element concentration which influence high temperature property are significantly changed during long term exposure or service. Therefore, it is necessary to make further analysis of the above precipitates evolution to optimize the organizational structure by adjusting the alloy composition or heat treatment, adjust or eliminate the harmful precipitation phase, improve the high temperature properties of the alloy.