W1002 excavator has been widely used in iron and steel corporations in northern China. As the main component of excavator, the dipper handle is the most important to design and manufacture. Because of the worse working conditions and large force, the dipper handle is still easily damaged and many fracture accidents have led to great economic losses of enterprises. The requirements of designing, if only based on the simple contracture strength calculations, are not enough. So it is necessary to study influence of the impact to service performance. In this paper the finite element method is used to analyze dipper handle and find out the weakness in the structure and factors impacting the service life of dipper handle. The improved dipper handle was used in the device and inspected by test instruments. The stresses are measured in same conditions in stall process and the results were also in consistence with the theoretical analysis. Improved model is fund out after using the 3D model to recalculate the stress. Since the improved dipper handle was used in practice to now, fracture accidents have not happened again.