Abstract: For 14MnNb steel of rolling state, with increasing the amount of rare earth in solid solution, the amount of NbC precipitation increase, the particles become smaller and uniform distribution. When the content of the rare earth in solid solution is 174×10^-6, these plated bainite microstructures turn to the particle ones. For austenite region, rare earth delay the start precipitation time of NbC, and reduce the effect of NbC precipitation. Rare earth in solid solution also delay the dynamics of recrystallization, and fine the martensite structure.