Abstract: Based on the research on physical metallurgy prediction model including the model of austenite recrystallization in microstructure evolvement, carbo-nitride precipitation, and relation between austenite phase transformation and structure-properties during strip control rolling and cooling, the austenite grain size of 0.16C-0.06Si-l.30Mn steel simulated calculated by computer after 7 pass hot deformation between 1 173 K and 1 081 K by Gleeble-1500 hot simulator was 43μm, mile the actual-measured austenite grain size in structure of strip after 7 pass deformation was 38 μm，the relative error was 13% . Therefore the austenite recrystallization grain size simulated calculated by computer better conform to that of actual measured value.