The navigation constellation design is involved in the optimization issues of many parameters. The goal of constellation design is to search a set of parameters and generate a navigation constellation using them. It is required that not only the optimal performance for the constellation needs to be the hest, but the cost of developing and maintaining the navigation satellite system is also low. Firstly, the indexes of evaluating constellation performance, algorithms of computing constellation availability and parameters of designing constellation are described in detail in this paper. There are three primary performance indexes examined, including the continued coverage, space distribution and redundancy. Secondly, as the navigation constellation design is a multi-objective optimization issue, the semi-analysis approach is presented simply in term of the practical engineering requirement. Only considering the central earth gravity, an ideal constellation can be designed from the aspect of geometry. The constellation parameters can be obtained synthetically and optimally in the case of meeting the constellation performance indexes. Therefore, four constellation schemes are generated optimally by using the approach. Finally, by analyzing the performance indexes and positioning simulation results respectively based on four schemes, it can be shown preliminarily that the semi-analysis approach and constellation schemes are feasible and rational.