Safe landing for spacecraft on moon or the other planets is the basic premise for carrying on field survey and sampling research. When it comes to the spacecraft safe landing, the environment the spacecraft confronts becomes more complex. So the selection of landing area would influence the success landing probability of the spacecraft directly. The paper stands in reality and takes the factors such as craters and stones into account abundantly, which affect safe landing for spacecraft. Considering of the radiuses of obstacle spots (craters and stones) and the edge conditions of predestination landing area, we could find out the optimal landing area with the help of Delaunay Triangulation.