In this paper, the parallel Conjugate Gradientmethod ( CG ) and Diagonal preconditioning Conjugate Gradient method ( DCG ) based on the technique of element-by-element ( EBE ) are described, which are used in the study of 3D electromagnetic fields by using finite element methods. 阐述了用有限元法求解三维电磁场问题时,基于单元接单元即EBE(element-by-element)技术的并行共轭梯度法(CG)和并行对角预处理共轭梯度法(DCG)方法。