三角分解法亦称因子分解法，由消元法演变而来的解线性方程组的一类方法。设方程组的矩阵形式为Ax=b，三角分解法就是将系数矩阵A分解为一个下三角矩阵L和一个上三角矩阵U之积：A=LU，然后依次解两个三角形方程组Ly=b和Ux=y，而得到原方程组的解，例如，杜利特尔分解法、乔莱斯基分解法等就是三角分解法(The triangular decomposition method, also called factor decomposition method, is a kind of method of solving the linear equation group by the evolution of the elimination method. A form of matrix equations Ax=b, triangular decomposition is the coefficient matrix A is decomposed into a lower triangular matrix and an upper triangular matrix L U product: A=LU, followed by the solution of two triangular equations Ly=b and Ux=y, and get the original equations, for example, Doolittle method, Jo Lessky decomposition is a triangular decomposition method)