Abstract:  Based on the hot simulation test  the effect of deformation condition and microalloying element 0.018  0.056NB, 0.01 - 0.02V and 0.01 - 0.02Ti on behavior of hot deformation of 0.06 - 0.08C test steel has been analyzed. And based on the Sellas-Tartat equation, the mathematic models to calculate the stress- strain curves have been established, that are dynamic recover model σ_(e)+ (σ_p+σ_o)[1-exp(-3.23ε/ε_s)]^0.5, where σ_p- peak stress, σ_o- stress at onset of plasticstrain, ε- strain,ε_s-strain to onset of steady state by work hardening and recovering, and dynamic recrystallization model - σ=σ=σ_(e)-(σ_p-σ_ss)｛ 1- exp[-2.363(ε-ε_c)ε_c^0.3425)²｝ , where σ_ss-stress to onset of steady state by dynamic recrystallization, ε_c- strain for onset of dynamic recrystallization. The predicted results to rolling force by the models conform with that of measured value of 0.07C-0.018Nb test steel during commercial rolling.