Effects of annealing temperature on microstructure and mechanical properties of Fe-18Mn-3Si-3Al TWIP steel were investigated by metallographic observation and tensile test. The results show that when the annealing time is constant,the annealing temperature determines the annealing grain size. Annealing grain size and its uniformity have significant effects on the mechanical properties of TWIP steel. Annealing above the recrystallization temperature within a certain range, the grain size increases uniformly ...