The invention discloses a steady-state flow simulation system for an air distillation tower, which comprises a field intelligent instrument connected with the air distillation tower, a control station, a database and an upper computer, wherein the upper computer comprises a signal acquisition module used for acquiring data of the current production working condition, and a calculation master module used for calculating. A process comprises the following steps: 1) setting structural parameters and operating parameters of the tower, and specifying an initial value of feeding air flow; 2) assuming components of a liquid phase of each tower plate; 3) for each tower plate, respectively calculating the equilibrium temperature and components of a vapor phase by a bubble point method; 4) for eachtower plate, calculating enthalpies of the vapor phase and the liquid phase; 5) calculating the flow of the vapor phase and the liquid phase of each tower plate through formulas (1) and (2); and 6) judging whether the following formula (3) is established, if so, stopping iteration and outputting a result, otherwise, updating the components of the liquid phase of each tower plate. The invention also provides a steady-state flow simulation method for the air distillation tower. The steady-state flow simulation system and the steady-state flow simulation method can accurately simulate the steady-sate flow of the air distillation tower.