Radar-absorbing materials(RAM), which effectively reduce the radar cross section of targets, are extensively used in stealth optimization of targets. Graphic electromagnetic computing(GRECO) uses graphic acceleration cards and Z-Buffer techniques to address blanking and non-visibility issues in traditional electronic magnetic algorithms. The traditional GRECO is improved to overcome its inability to precisely extract geometric information on visible surfaces and the dependence of calculation accuracy on screen resolution. An algorithm that can calculate the multiple scattering of metal dihedral-coated RAM is proposed. In addition, the element search method used in traditional dihedral calculation is improved, and calculation time is reduced by a significant margin. After the experimental results were compared, the accuracy of the algorithm is examined. The proposed algorithm, combined with the improved GRECO, can used to analyze the stealth performance of complicated targets coated single- or multilayered RAM. Radar-absorbing materials (RAM), which effectively reduce the radar cross section of targets, are extensively used in stealth optimization of targets. Graphic electromagnetic computing (GRECO) uses graphic acceleration cards and Z-Buffer techniques to address blanking and non-visibility issues in traditional electronic magnetic algorithms. The traditional GRECO is improved to overcome its inability to precisely extract geometric information on visible surfaces and the dependence of calculation accuracy on screen resolution. An algorithm that can calculate the multiple scattering of metal dihedral-coated RAM is proposed. After the experimental results were compared, the accuracy of the algorithm is examined. The proposed algorithm, combined with the improved GRECO, can used to analyze the stealth performance of complicated targets coated sin gle- or multilayered RAM.