An analysis method of designing transmission lines of an integrated circuit packaging board including an integrated circuit chip, a printed circuit board, and an interposer disposed between the integrated circuit chip and the printed circuit board. A reference data file having information for dividing a series of transmission lines into connecting sections and/or continuous sections and a division model file having information on analysis models of a connecting section and a continuous section is prepared. The connecting sections are extracted from the series of transmission lines with reference to connection information. Boundaries for dividing the series of transmission lines into sections is determined with reference to the reference data file to generate division models. The division models are synthesized to form a synthesized model of the series of transmission lines to analyze electrical characteristics of the series of transmission lines.