A three dimensional finite element model of the heat treatment process of ZG06Cr13Ni4Mo stainless steel was established in this paper. The distribution of stress and deformation for large hydro turbine blade with complex surface during normalizing and tempering treatment has been simulated. The simulated results are consistent with the measured equivalent stress values by hole-drilling method, which indicates that the model is effective to predict the stress distribution of heat treated ZG06Cr13Ni4Mo material. Based on this model, the distribution law of stress field and deformation of the large hydro turbine blade of complex surface after the heat treatment were simulated. The established model provided a theoretical prediction method for designing of optimized complex surface blade and formulating a reasonable heat treatment process.