Cross wedge rolling valve roughcast is charactered by minor diameter, long stretching and heavy section shrinkage; however, it is hard to select a set of suitable machining process parameter and prone to rolling internal defect. In order to research this problem, a whole forming process of valve roughcast by single cross wedge rolling is simulated with finite element simulation software DEFORM-3D 6.0, which focuses on the stress and strain of the center point of rolled piece under different forming angles. The rolling experiment under different forming angles was done on H500 rolling mill to calculate and analysis of the areas of the centre holes for each rolled piece. The influence of forming angle on internal defect is discovered by a method combining finite element simulation and experiments. At last, it is concluded that forming angle of 28°can improve the internal defect of valve roughcast formed by single cross wedge rolling.