The Environment Assessment of Restricted Development Zone is intended to evaluate the preservation value of RDZ and is used as a major tool for RDZ adjustment. 20 years have passed since the EA began, but there is a lack of discussion about EA. In this paper, the EA was reviewed, the characteristics of the EA were revealed, and proposed the problems and improvement measures. Due to the evaluation method of EA, some of six index had a relative superiority. In addition, among the 6 index, there was an index that were difficult to be considered as index of ecological environment conservation value such as elevation, slop, agricultural suitability. Although it is necessary to continuously update the EA grade, only some index can be updated due to characteristics of raw data. The adjustment of RDZ is expected to continue in the future. Therefore, in terms of urban growth management, it is necessary to use a clear basis for adjusting RDZ or to introduce improvement measures to overcome the problems of EA.