Abstract: A simulation system and a method thereof are disclosed. In the simulation system, a system power transmission model, and analog current time-domain model and digital current time-domain model are connected to obtain power noise generated after a supply current is obtained; jitter time-domain information of each interface connection circuit model under the power noise is obtained based on transmission of a clock signal outputted from a phase lock loop, by a simulation program; next, a voltage step response of a voltage measurement point when a clock terminal of each interface connection circuit model receives an ideal signal, is simulated by the simulation program to generate a first voltage time-domain model; a system waveform is generated based on the jitter time-domain information of each interface connection circuit model under the power noise, the first voltage time-domain model and data transmission, thereby obtaining an eye diagram and time-domain jitter distribution.