Due to the ever-increasing air traffic flow,the influence of aircraft noise around the airport has become significant.As most airlines are trying to decrease operation cost,stringent requirements for more simple and efficient departure trajectory are on a rise.Therefore,a departure trajectory design was established for performancebased navigation technology,and a multi-objective optimization model was developed,with constraints of safety and noise influence,as well as optimization targets of efficiency and simplicity.An improved ant colony algorithm was then proposed to solve the optimization problem.Finally,an experiment was conducted using the Lanzhou terminal airspace operation data,and the results showed that the designed departure trajectory was feasible and efficient in decreasing the aircraft noise influence. Due to the ever-increasing air traffic flow, the influence of aircraft noise around the airport has become significant. As most airlines are trying to decrease operation cost, stringent requirements for more simple and more efficient departure trajectory are on a rise. Herefore, a departure trajectory design was established for performance based navigation technology, and a multi-objective optimization model was developed, with constraints of safety and noise influence, as well as optimization targets of efficiency and simplicity. An improved ant colony algorithm was then proposed to solve the optimization problem .Finally, an experiment was conducted using the Lanzhou terminal airspace operation data, and the results showed that the designed departure trajectory was feasible and efficient in decreasing the aircraft noise influence.