Abstract: In view of the problem of eutectic carbide in hot work die steel forging H13 steel of small size,by using acid washing、OM and heat treatment experiment,influences of homogenizing annealing time on microstructure and eutectic carbide of small forging piece of H13 steel were studied. The results were that after 5 hours of homogenizing annealing for H13 steel,there were no widmanstatten structure and burned grain boundary.5 hours can be the best annealing time for homogenizing annealing of forging H13 steelof small size.