3D IC is developing as an incredible response for the next generation system packaging and integration technology to accomplish low power utilization, high channel transfer speed and high-density integration capability simultaneously. With respect to the vertical interconnect for a 3D IC, through-silicon via (TSV) is a key part which can produce a myriad performance improvement with the extraordinarily decreased length of interconnects among vertically stacked dies. In this paper, the electrical equivalent model of a TSV is proposed and the electrical behaviour of three coupled TSV with the variation of length, diameter, and pith parameters are analysed.