Abstract: The condenser throat with the inner low-pressure heater and exhaust of turbine driven feed pump of some steam turbine is 3-D numerically simulated using the k-ε model combined with wall-function method and the SIMPLEC algorithm,and the non-uniformity of flow field and the change of energy loss coefficient are analyzed.Results indicated that,the low speed areas are formed at four angles of the condenser throat outlet section.For the inner low-pressure heater,the low speed eddy zone is formed just below it.The non-uniformity of flow field is increased for the existence of exhaust of turbine driven feed pump,because two partial low speed areas are formed at the outlet section near the side of the exhaust of turbine driven feed pump.The velocity distribution nearby the exhaust of turbine driven feed pump is only affected,however far away from it,the velocity distribution of throat flow field is hardly affected but the values are increased.At rated conditions,the energy loss coefficient with exhaust of turbine driven feed pump is increased compared with that without exhaust of turbine driven feed pump.