本文指出了单位模阵与连分式的一种对应关系。根据这一事实,把矩阵序列结构算法用于系统降阶问题。其结果包含了第一,第二 Cauer 形连分式降阶法,有效地克服了连分式降阶法在 Routh表首列出现零元素时遇到的困难。这种方法既便于手算,也适合在计算机上运算,它还具有在一次施行结构算法过程中同时获得各阶降阶模型的特点。 This paper points out a correspondence between unit matrix and continued fraction. Based on this fact, the matrix sequence structure algorithm is applied to the system reduction problem. The result consists of the first and the second Cauer-type fractional reduction methods, which effectively overcome the difficulties encountered by the fractional reduction method in the appearance of zero elements in the first column of the Routh table. This method is both hand-calculated and suitable for computing on a computer. It also has the characteristic of simultaneously obtaining reduced-order models of various orders in a single execution of the structural algorithm.