Abstract: Wassell’s model and experimental correlations were synthesized.The effects of Reynolds number were taking into consideration to modify the characteristics of compressors and turbines.The performance and aerodynamic stability of three turbofan engines were calculated with modified compressors and turbines characteristics.Investigation shows that:Reynolds number almost has no influence on the engine performance and aerodynamic stability at low altitude,but has significant influence at high altitude with low flight speed.The turbine inlet total temperature and engine thrust are increased.The percentage increase of thrust and specific fuel consumption are 3%～6% and 8%～10% respectively,while the engine surge margin is decreased in the range of 19%～39%.It means that the effects of Reynolds number must be taken into account in turbofan engine performance simulation at high altitude with low flight speed.