A new idea of expoliting the ”guidance information” to get more computation efficiency for circuit simulation has been proposed. The guidance information used is the strength of signal flow and is cooperated with Iterated Timing Analysis algorithm (ITA) to get better simulation performance in dealing with large-scale MOSFET circuits. Derivations of calculation methods for strength of signal flow, and algorithm details are all stated and implemented. Several large-scale examples circuits are tested for the implemented program, whose results are quite pleasing. This new method pertains all advantages of ITA algirithm (it's robust, good at simulating tightly-coupled circuits, accurate, flexible and so on). Moreover, this new method provides additional advantages, such as ability of utilizing both multirate and latency behaviors of simulated circuits, and having a lower computation time complexity. All benefits earned by this new method are all justified by experimental results. The new method has demonstrated a brand new approach to enhance the efficiency of algorithms in solving the circuit simulation problem. which has made a significant progress. We think the result of this paper can have important contribution in circuit design community. We also believe the novel ieda of simulation with guidance information is very valuable and can be adopted in other researches to get more successes.