In modern circuit design community, to perform large-scale circuit simulation for MOSFET and interconnect circuits is an important subject. This paper presents an efficient and robust way to satisfy this requirement. It uses ITA (Iterated Timing Analysis) algorithm, serving as the main algorithm, and a transmission line calculation algorithm, serving as the interconnect calculator, to do the simulation task. More important, accelerating methods to fasten both ITA and the transmission line calculator also proposed in this paper. All presented methods have been implemented and tested to justify their efficiency and robustness.