In this paper，the connection between the attenuation characteristics of Chebyshev impedance-transforming network and Chebyshev low-pass fi1ter is estab1ished by selecting an appropriate transforming function. In this way，on the basis of network functions of low-pass fi1ter the calculating formula of element values of impedance-transforming network can be derived by means of network synthesis. Application of these formulas to design impedance-transforming network and application of the correspondent table of element values to do so are mutual1y complementary，Final1y，through an example the method of using the derived formula to calculate network element values is illustrated.