In order to avoid crack and fracture of the second stage rotor blade of a certain aero-engine low compressor, a new remodel plan is used. That is to thicken the rotor blade and to strengthen the flange. The mechanic properties of the blade and the disc before and after being remodeled are studied in this paper so as to verify the intensity and its influence on the disc. The conclusion is that the stress distributions on the blade and on the disc are not changed and, the magnitudes and the intensity of the stress all meet the design standards. These jobs provide a theoretical basis for replacing the unimproved blades by the improved ones and a theoretical foundation of preventing the blade and the disc from cracking and fracturing.