Abstract: A set of thrust charateristics (thrust with nozzle pressure)of a round covergent nozzle、five lobed nozzles and lobed nozzle-mixing tube combinations with and without difffusers have been obtained from the experimental investigation at cold high speed conditions (nozzle pressure=0.15～0.5 MPa) Test results show that the lobed nozzles of the exhaust ejector systems at high speed conditions also have superior application prospects,provided their designs consider the impact of high speed flow,in especial,the aerodynamic charateristics of supersonic exhaust flow.