Abstract: The conventional design methods of helicopter nacelle exhaust ejector mixing tube were introduced.Based on the characteristic equation and analysis of influence factors,and with a reference to nacelle exhaust systems of a helicopter,an improved design method of helicopter nacelle exhaust ejector mixing tube was established.Based on this improved method,a helicopter nacelle exhaust mixing tube was designed as an example.By comparing with other design results,this method could improve the design efficiency by 30% and maintain design accuracy within 5% to meet the engineering design requirements,demonstrating its availability and significance in engineering applications.