The nation that announced ”Completeness Ratio” at the earliest stage is Japan. The meaning of ”Completeness Ratio”: ”in order to reach the target of the managing of watershed, need to be put into of manage total and the comparison for managing that complete already currently”. (Japanese construction province, 1958). This research aims at the formula of Completeness Ratio of Japan and Taiwan and it various parameters carry on a research. Revise Completeness Ratio of difficult and actual calculation up of problem. Besides, according to after problem analyze, this research puts forth two sets of ”revise behind Completeness Ratio ”formula. The first, for ”with the watershed manage for basal index (CRS1)”. The second is ”the sediment of watershed downstream export-based index (CRS2)”. Also take three watersheds as an example, carry on the calculation of case.