Abstract: The effect of Reynolds number on the characteristics of the Low Pressure Turbine (LPT) was investigated and the variations of flow structures with Reynolds number were analyzed by numerical simulation.The results show that the efficiency of LPT is decreased with the reduction of Reynolds number,and the relationship between the efficiency and Reynolds number change is non-linear.Obvious changes of blade surface velocity distribution at different Reynolds number can be found,which induce the increases of profile loss and secondary flow loss.The results also show that the design of blade surface velocity distribution has significant influence on turbine characteristics change with Reynolds number.It is very important to the aerodynamic design of LPT which is intended to operate at low Reynolds number conditions.