Abstract: Current solutions of configuration of ground-based pseudolite navigation system cannot meet the emergency application demand because their time-complexity is too high and the results are not optimal enough. To solve this problem, an algorithm named optimization searching based on maximum convex-hull (OSMC) is proposed. In OSMC, all location points which pseudolites can be placed on are evaluated according to the maximum convex hull theory, the result of evaluation is the importance of a location point. The more important a location point is, the higher scores it can get. After all location points are evaluated, we have an overall result of all location points. From the overall result we can find out the location points which are suitable for being set up as bordering pseudolites or central pseudolites, in the global optimum constellation. When the points having lower scores are excluded, the rest points would have the higher probability to constitute the best constellation. Exhaustive method is used in the remain points to search the best constellation. OSMC can be used in irregular areas to get a quasi-optimal pseudolite distribution rapidly. The simulations of OSMC in practical examples confirm that OSMC can truly get the quasi-optimal constellation in much shorter time than the other current solutions, and the results are optimal enough, which meets the demand of emergency applications.