In the trends of high density, high speed and low power consumption, the analysis of power distribution networks is rapidly becoming an essential step in the design of high performance ICs. Nevertheless, the analysis is a great challenge, due to the large size of the networks. In this paper, we propose a variable reduction technique for the analysis of large-scale power distribution networks. The basic procedure of the proposed technique is reducing the power distribution network to a manageable size, solving the equation of the reduced network and then recovering the solutions of the original network. With the proposed variable reduction technique, we have achieved speed improvements up to several tens of times compared to the high performance linear system solution techniques with no loss of accuracy.