Airspace traffic complexity measures the airspace internal structure objectively， which is one of the main factors affecting the sector planning. In order to make use of the aerospace resource reasonably and improve the operational efficiency of air traffic， the sector planning problem is studied based on complexity analysis. By considering the aerospace internal structure and operating status， the characteristics of the sector area， airline construction， cross complexity， model and operation combination conditions are analyzed deeply. Then， the quantifiable evaluation index of airspace traffic complexity is established to define the airspace traffic complexity， which measures the controller′s workload. The sector planning model is built based on the principles of balancing the controller′s workload， and the model is solved by using the growth algorithm. Finally， taking the airspace of the Pearl River Delta region as a simulation example，result indicates the effectiveness of the method.