Mare basalts, one of the rock types in the moon, mainly occur in the large impact basins. The filling process of mare basalts including the flowing patterns and the scales has implications for understanding the evolution of the impact basin and thermal evolutional history of the moon. In this paper, the charateristics of topography and chemical compositions of rocks in Mare Imbrium were extracted using combination of CE-1 LAM data, CCD data and Clementine UVVIS data. Then mare basaltic units were defined, and surface ages of the defined basaltic units were evaluated using the Crater Size-Defrequency Distribution measurements. Relationships among topography, chemical compositions and surface ages of mare basaltic units in Mare Imbrium indicate that the younger in surface ages of the basaltic units, the more enrichment in Titanium and Iron, exactly from low Titanium, low Iron in Late Imbrium to high Titanium, high Iron in Eratosthenian. The filling process is multi-staged with northward stepwise almost in every stage in Mare Imbrium. With the scales of mare basalts minishing gradually, the extent of relatively younger basaltic unit covering older one becomes smaller and smaller. It is the relationship between filling process and coverage that results in topographic changes and distribution of the surface ages of basaltic units. Therefore, a mode of multi-staged with northward stepwise almost in every stage and gradual minishing scales was suggested.