The invention relates to the field of heat treatment of iron and steel materials, particularly to a heat treatment method for accelerating the aging of a T/P91 heat-resistant steel. The method comprises: carrying out rapid high-temperature short-term aging accelerating on a substrate and a carbide, and ageing at a temperature of 20 DEG C below the AC1 point; ageing at a temperature of 620 DEG C after completing the aging to ensure the rapid precipitation of the Laves phase, such that the aging structure equivalent to the actual working condition at different stages is achieved. According to the present invention, with the aging accelerating method, different degrees of the aging structures of the T/P91 heat-resistant steel can be rapidly obtained; by comparing the aging accelerating structure to the actual working condition, the aging accelerating test can achieve the technical effect of the accurate and reliable equivalent simulation; and with the method, the technical problem that different degrees of the aging structures during the whole use stage cannot be obtained due to the short service time of the T/P91 heat-resistant steel so as not to perform the effective aging grade evaluation in the prior art can be solved.