Based on the characteristic of aviation nozzle-ejector's wake-flow field,the modeling of study the flow in the nozzle-ejector and wake-flow field is conducted through numerical simulation, the whole flow field’s basic parameter with the model is got.Analyzing the flow field of the nozzle-ejector’s exhaust plane and validating the model through the experiment of certain aero-engine,the result indicates that the model can reflect the wake-flow field practically. At last,the thrust of every nozzle-ejector is calculated by the way of area element and the thrust loss of the lobe nozzle-ejector relative to the 1st nozzle-ejector is got.