The Generators used in aerial industries should have the characteristics such as high efficiency, power density and reliability, low weight and volume. Among different generators, permanent magnet synchronous generator adequately satisfied these requirements. In this paper, first the dimensions and other quantities of this generator are calculated through an analytical model. Then using Cuckoo Optimization Algorithm (COA), these quantities are optimized to suit for desirable needs of aerospace systems, in order that the total volume of the generator could be minimized and its efficiency could be maximized. The results of this design for the permanent magnet synchronous generator application in aerospace systems have been satisfactory.