Abstract: The influencing factors of oxidation discoloration of 05Cr17Ni4Cu4Nb stainless steel were investigated by using different vacuum aging treatment technological systems. The results show that 05Cr17Ni4Cu4Nb steel was sensitive to the vacuum aging atmosphere, and the oxidation discoloration was mainly relevant to the high chromium content. In order to avoid surface oxidation discoloration of 05Cr17Ni4Cu4Nb steel, it was better to carry the vacuum aging treatment in reducing atmosphere. If the aging treatment was carried out in the existing vacuum weak oxidizing atmosphere, in order to keep the sample surface color invariant, the tapping temperature should be reduced to 60 ℃. When acetone ultrasonic cleaning was applied, the oxidation discoloration problem of aging treatment sample could be effectively improved.