Gully erosion is a common phenomenon of soil loss. The quantitative study on gully erosion can unveil more its law. This would provide some scientific basis to establish predicting models and to assess the harm of it and how to govern it. This paper introduces briefly some quantitative study methods on gully erosion in the past several years and gives comments about those that include the proper scope and the advantages and some limitations and points out some problems solved in the future and study direction.