Abstract: Picture analysis method is used to measure and analyze the carbide distribution in the high-speed steel shaped by radial forging machine. The method can remarkablly reduce the error caused by using the comparing pictures of carbide degree to appraise the quality of high-speed steel. Following four factors are measured:(1) area percentage; (2) average area of grain; (3) average free distance; (4) length-width ratio. Based on these factors, the process of radial forging is discussed and the relationships between the factors and accumulated deformation degree, or the final deformation temperature, are oblained. The increase of the accumulated deformation degree and a reasonable amount decrease of the final deformation temperature (860-910℃) are favourable for the fineness of carbide.