Abstract: This paper presents an efficient method for analysis of mesh-structured RLC power distribution networks in time-domain. The algorithm uses a new heuristic-based coarse grid construction technique to extend the geometric multigrid method to solve power distribution grids modeled as RLC circuits for the first time. Experimental results show that at least two orders of magnitude speedup over SPICE is observed on some large P/G networks with a little accuracy loss. For instance, power/ground networks with more than one million nodes can be solved in half a hour on modern Sun workstations with 1.5% errors.