Abstract: Tensile test was performed to 304 austenitic stainless steel, and the serrated flow behavior during high temperature tension deformation was studied. The results show that the temperature for happing dynamic strain aging was 773-973 K when the strain rate within the range of 2×10-4 to 2×10-3 s-1. The typed of A, A+B and E serrated wave and negative strain rate sensitivity coefficient appeared, and the effective activation energy for forming serration was 212.8 kJ·mol-1. The dynamic strain aging happening for the tested steel was because of the interaction between substitutional atoms (Cr, Mn and so on) and moving dislocations, and then caused serrated flow behavior happening.