Nowadays the applicability of the electromagnetic induction quenching approach has diffused to the engine industry, especially for the parts made by metal materials such as the crankshafts. In this paper, quantitative study was adopted in researching the strengthening effect of this technique. First the multi-physics simulation was achieved to carry out the key information caused by this approach such as the temperature and residual stress distribution property. Then the fatigue limit load was predicted on account of the simulation results and the stress field intensity approach. Finally the feasibility of this prediction method was checked through standard bending fatigue experiment. The conclusions proposed from this paper is that the prediction method can provide accurate results in keeping with the experimental results, which makes it has very wide popularization and application prospects.