The method includes three procedures: pretreatment procedure, node evaluation procedure, and real time processing. The method includes following steps: reading geography data from hard disk; next, through pretreatment procedure, converting sampled geography data to data to be stored in another data format; then, when rendering topography, the real time processing procedure carries out rendering topography in real time based on evaluation on detailed degree of topography node by the node evaluation procedure; finally, repairing cracks generated in rendering topography. Optimizing traditional geomorphic algorithm, the invention raises generating efficiency and speed, enhances variability of geography in game scene.