Water level is an important index for studying hydrologic processes. Water level rise processes were studied in three catchments(catchment I, II, III in Chen Jiagou watershed in the Three Gorge Reservoir Area) with different areas to provide useful information to inform data extension from a gauged-catchment to an ungauged catchment. The results showed that there are seasonal changes in the dominant driving mode of the rise of the water level. The rise of the water level in March is likely mainly driven by the mode of stored-full runoff, and in September or October, it is mainly driven by Horton-flow. The correlation coefficients of all indexes were significant among the three catchments, suggesting that these catchments have similarities and that water level data extension is likely to be completed successfully between the large catchment(III-Catchment) and the small catchment(ICatchment). It was confirmed that there is good similarity between the 0.6 km~2 and 6 km~2 catchments, and the data correlation is good between the catchments with the area differences in the Three Gorges Reservoir Area. In addition, the rise processes of the water level in the catchments were not only different under the same rain conditions, but this difference could also change with the rain condition. Water level is an important index for studying hydrologic processes. Water level rise processes were studied in three catchments (catchment I, II, III in Chen Jiagou watershed in the Three Gorge Reservoir Area) with different areas to provide useful information to inform data extension from a gauged-catchment to an ungauged catchment. The results showed that there are seasonal changes in the dominant driving mode of the rise of the water level. The rise of the water level in March is likely mainly driven by the mode of stored-full runoff , and in September or October, it is mainly driven by Horton-flow. The correlation coefficients of all indexes were significant among the three catchments, suggesting that these catchments have similarities and that water level data extension is likely to be completed successfully between the large catchment (III-Catchment) and the small catchment (ICatchment). It was confirmed that there is good similarity between the 0.6 km ~ 2 and 6 km ~ 2 catchments, and t In addition, the rise processes of the water level in the catch of were not only different under the same rain conditions, but this difference could also change with the rain condition.