304 austenitic stainless steel is a common structural material used in the nuclear power plant, and its basic mechanical property would be changed by work hardening, which seriously affects the evaluation of the integrity of the nuclear power structure. The relationships of between the yield strength and the reduced modulus ratio (σ0.2/Er) with the residual indentation depth and maximum depth ratio (hr/hm) during cold work processing of 304 austenitic stainless steel is analyzed by using theoretical analysis, experiment and finite element simulation, and an approximate analytical model to expressσ0.2/Erbyhr/hmis established in this paper. The investigating results indicate that yield strength, Vickers hardness, andσ0.2/Erwill increase, andhr/hmdecreases with the material deformation increasing, and the analytical result of theσ0.2/Erbasically consistent with the experiment result.