Many studies since 1977, in the southern coast of Caspian Sea revealed that the law-setback and low-lying coastal zone have been severely and increasingly impacted by rising sea-level. This rising continued until 1995. The rate of rising was nearly 13cm per year in this period (1977-1995). The general concept of setback determination is tended to introduce a buffer area between human activities (especially buildings) and a shoreline that is likely at the highest risk of sea-level rise and following damages. This study could help managers to solve many problems in the future, noticeably due to lack of criteria for determination of setback in this region. In this study a setback is introduced on the basis of critical levels of Caspian Sea and the results of coastal vulnerability assessment to sea-level rise in Mazandaran Province. This setback is composed of two parts called, vertical buffer and horizontal buffer. In this study, the CVI (Coastal Vulnerability Index) method is used for coastal vulnerability assessment to sea-level rise. The CVI includes 5 variables describing two dimensions, natural and anthropogenic. Final map is divided into 4 classes from low to very high vulnerable. Mean distance between very high vulnerable classes to the vertical buffer boundary is introduced as a horizontal buffer in each district.