Meta-stable austenitic Cr-Ni steels were cold rolled and reversion treated under various conditions to develop ultra-fine grain structure, and the tensile properties of these steels were analyzed. The steels demonstrated the yield point behavior which is often observed in law carbon ferritic steels. The difference between upper and lower yield points was decreased and the amount of yield paint elongaton was reduced, as the grain size was coarsened. This behavior was closely related with the austenite stability. Steels reversion treated at high heating rates underwent diffusionless transformation. The yield stregnths of these steels were lower than those treated at slow heating rates which underwent diffusional transformation. The Hall-Petch relation appeared to hold in the present steels, but the linearity between the inverse square root of grain size and the yield strength was gradually diminished as the grain size was ultra-refined. It was suggested that approriate combinations of the alloy chemistry and the thermomechanical processing condition enabled development of ultra-fine grain high strength austenitic steels with yield strength as high as 1200MPa.