Abstract: This paper studies the forging productive technology,microstructure and property of SM55 cavity forging die block. The results show that we can produce SM55 cavity die block though the productive technology include that repeatedly forging times and directions,controlling the rolling reduction of different forging times and directions, using specialtools forging the cavity. The outline of cavity forging die block is excellent. We have tested the vertical mechanical property and microscopic structure of SM55 cavity die block. Tests have shown that SM55 steel cavity forging die blockcan satisfy requirements ofthe using measures.