The invention belongs to the field of high-temperature alloys, and particularly relates to a gamma' phase reinforced cobalt-based high-temperature alloy with high-stability structure and good oxidation resistance. The gamma' phase reinforced cobalt-based high-temperature alloy comprise the following chemical components of, by weight, 2.5-4% of Al, 3-10% of W, 0.5-5% of Ti, 1.5-6% of Ta, 18-35% ofNi, 10-14% of Cr, 0-4.5% of Nb, 0-0.5% of Hf, 0-0.1% of C, 0-0.1% of B, 0-0.1% of Zr, 0-0.5% of Si, and the balance Co, and the contents of Al plus Cr is more than or equal to 13.5%, the Al plus the Ti plus the Ta plus the Nb are more than or equal to 9.5%, and the W plus the Ta is less than or equal to 12.5%; and a vacuum arc furnace is adopted for smelting, then solid solution is carried out atthe temperature of 1200-1250 DEG C, and aging heat treatment is carried out at the temperature of 700-900 DEG C. The gamma/gamma' two-phase structure stably exists at the temperature of 700-900 DEG C,and the gamma' strengthening phase volume fraction is larger than 40%; and meanwhile, the alloy has good oxidation resistance, large hot working window and low alloy density, and is an alternative material of a high-temperature disc piece of an aero-engine and an industrial gas turbine.