The transformation behavior of Nb-V micro-alloyed low carbon steel during continuous cooling was studied through thermomechanical simulator and metallographic analysis. The results show that the dynamic CCT diagrams shift to the left and upper compared with the static ones, the begin temperature of γ→α transition is gradually lower with the increase of cooling rate. The high temperature deformation decreases Ferrite transition zone. When the cooling rate is lower, the deformation improves Bainite transition; when the cooling rate is higher, the deformation inhibition Bainite transition.