Abstract: In 2017, China issued the “Regulation on Coastline Protection and Utilization Management”, which was set up specifically for the coastline management. For the first time, “ecologically restored coastline” was introduced into the statistical scope of natural coastline retention rate. This innovation has significantly promoted the subsequent development of China’s coastline management and restoration works, at this circumstance, it has become a very necessary and important issue to scientifically assess the degree of the natural attributes of the coastline. By taking China’s mainland coastline as a case study, the following works were carried out: Based on the substance of natural attributes of coastline, the requisite conditions for coastline to have natural attributes were clarified, and the theoretical framework for the assessment of natural attributes of coastline was constructed, that is, on the basis of determining the presentational typology of coastline, impacts of both land and sea on the coastline were taken into account. And, based on multi-factor data and GIS spatial analysis techniques, starting from the three dimensions of coastline own attributes, land impacts and marine impacts, the quantitative assessment methodology of coastline natural attributes with a three-level structure of "target level-criterion level-index level" was constructed by selecting the shoreline section as the basic assessment unit. The assessment results of the natural attributes of China’s mainland coastline showed that the total length of the coastline of high and extremely high grades accounted for 41.7%, which was higher than the length-proportion of the unused coastline (35.1%). The extremely high grade of natural attributes of the coastline was mainly distributed in the Liaohe estuary, the Yellow River Delta, Yancheng and Hong Kong. The natural attributes of the unused shoreline were the highest, and the tidal embankments, salt pan embankments and aquaculture embankments were subject to different degrees of human disturbance, but some of them had much better ecological and environmental conditions, therefore their natural attributes were classified as high or extremely high grades. Overall, this study can provide strong support for the scientific monitoring and sustainable management of coastline resources in China.

Key words: Coastline, Natural attributes, Quantitative assessment, Land impacts, Marine impacts, Indicator system