The tiny defects that are introduced into turbine discs by the polytechnic process of powder metallurgy (PM) tend to be the initiation points of fatigue cracks under cyclic loadings, and the actual service life of a turbine disc may be shorter than its design life limit, and this can lead to disaster accidents. On condition that PM defects cannot be avoided completely with current technological process, it is necessary to develop and establish the computation method of the actual service life for turbine discs containing defects to ensure that the commercial aircraft engines of our country can acquire type certification and march into the international market. Based on finite element stress analysis, the stress intensity factors are calculated according to the circumferential tension stress in the vicinity of the defect; to simulate the crack growth process, the major axis and minor axis of the embedded crack, as well as the coordinates of its center, are updated gradually based on Pairs law in a cycle-by-cycle way, and finally the computation method of the actual service life for turbine discs containing defects is established, using the failure criteria of critical fracture toughness. Taking the stage 1 turbine disc containing defects as an example, this method can compute the actual service life of a turbine disc containing defects before disc burst, and can obtain the variation curves of the defect shape, defect area, and stress intensity factor with flight cycles, according to the results of ultrasonic nondestructive testing. Accuracy verification was made by performing a three-dimensional finite element simulation of crack growth, and it is found that the proposed method tends to obtain a more conservative result of life computation (relative error is 2.82%), and have distinct advantage in computation efficiency.