Concrete materials have variable behavior of chloride penetration because there are unstable factors such as pore structure, chemical reaction, cracks, etc. In order to consider variables containing uncertainty, recent research has tried to introduce the design of concrete durability based on probability theory instead of deterministic theory. In this study, the chloride-attack fragility curve that takes into account the statistical characteristics of concrete materials is proposed. It can reflect uncertainty unlike the existing chloride-attack resistance evaluation method. In order to efficiently perform a large number of tests required for this, a new test method referring to ASTM C 1202 and NT BUILD 492 was proposed and tested. As a result, it was possible to validate the appropriateness of the proposed curve, and to compare the chloride-attack resistance properties of cement mortar with alkali-activated slag mortar, including its uncertainty.