Abstract: In this paper, the concept about one-symbol network functions is presentep and the separating form of node admittance matrices is founded. The formulas for calculating determinants, 1-cofactors, and 2-cofactors of node admittance matrices are derived by using the number-symbol separating algorithm. On this basis, the formulas for calculating one-symbol network functions are given. By using these formulas, we can obtain any network functions which make any component parameter a symbol. This is a polynomial complexity algorithm, so it is an efficient algorithm. Furthermore, it is convenient to realize this algorithm by computers. This algorithm is suitable to largenetworks.