Abstract: The dendrite growth behaviors and solidification microstructure of high carbon medium manganese wear-resistant steel (medium manganese steel) were systematically investigated by means of series of directional solidification experiments, metallographic microscope and theoretical calculation. The results calculated by Factsage showed that the microstructure transformation of the medium manganese steel was L → L + γ → γ, and there is no peritectic reaction and no δ phase and other phase appeared. Under the experimental conditions, the solidification structure of medium manganese steel were developed dendrite structure, and there was no cell/dendrite transformation. In addition, the dendrite spacing of medium manganese steel decreased with the growth velocities increased, which was consistent with the steel with low alloys.