Abstract: In order to calculate and meet the rational intersection angle and plate length of the guide plate in the bilateral plow type unloader of the belt conveyor u nder the stress condition, the paper analyzed the stressed features of the bilateral plow type unloader applied in the belt conveyor and derived the extrusion and shear strength condition formula of the unloading guide plate .According to the momentum conservation law in the theoretical mechanics, with the dynamic impact force of the moving material to the unloading guide plate calculated was put in the compression and shearing strength condition formula, the relationship between the intersection a ngle of the bilateral plow type unloader and the direct stress of the unloading guide plate and the relationship between the plate length of the guide plate and the shear stress in the bilateral plow type unloader were derived.The MATLAB software was applied to have the relationship curve of the intersection angle, shear stress and dire ct stress of the guide plate and find out the law and features in the curves.With the analysis, the conclusion on the bilateral plow type unloader optimization of the belt C onveyor was provided and the intersection angle of the guide plate in the bilateral plow type unloader of the belt conveyor was proposed as 40°90° .With a related formul a, an rational length of the guide plate could be obtained.