Abstract: In this paper, a novel method is proposed for the equation formulation of BUS interconnect circuits. Band-symmetric matrices of the system equations are formulated by taking advantage of the parallel structure of the BUS interconnects. The bandwidth of the system matrix is 2n+1, where n is the number of the BUS lines. Compared to the conventional modified nodal equation formulation method, the proposed method can remarkably improve the simulation speed of the BUS interconnects. The proposed method can be easily applied to circuit simulation tools such as SPICE, PRIMA, PVL, for the interconnect simulations.