本文介绍了一种用于求解人体胸腔三维恒定电场有限元方程组的算法。该算法采用直接法中克劳特分解法与分块技术相结合来求解已合成的总体有限元方程组， 从而解决了计算机因内存有限而使程序经常死机的问题。该算法已成功地应用于心阻抗血流图三维有限元建模的理论研究中。 This paper presents an algorithm for solving three-dimensional finite element equations of the human chest in constant electric field. This algorithm uses the direct method in which the Klot decomposition method and the block technology are combined to solve the synthetic finite element equations, thus solving the problem that the computer often crashes due to the limited memory. The algorithm has been successfully applied in the theoretical research of 3D impedance finite element modeling of heart impedance blood flow graph.