<p> An index parameter called the maximum area shrinkage-cracking ratio <i>SCR</i> and a corresponding classification procedure are proposed to identify and classify expansive soils. <i>SCR</i> is defined as the ratio of the total area of shrinkage cracks of soil after drying to the initial surface area of the soil sample in a standardized mold. In this paper, the basis for the new method is illustrated, and the testing procedure is validated using expansive soils obtained from eight districts in China and two places in the US. The effect of three factors, namely, initial water content, initial sample thickness, and mold surface roughness, that can influence the proposed testing procedure and parameter, were investigated. Following its experimental validation, a classification system based on the maximum area shrinkage-cracking ratio is recommended. Validated by the experimental findings, a classification system based on the maximum area shrinkage-cracking ratio is recommended. Furthermore, relationships among the maximum area shrinkage-cracking ratio, cation exchange capacity, and particle size distribution of the soil being tested were analyzed. Linear relationships between these parameters indicate that the maximum area shrinkage-cracking ratio can reflect the nature and characteristics of the shrinkage and cracking of expansive soils. Although other existing methods with sufficient accuracy are available, statistical results illustrate that the proposed method presents higher reliability of test results. The maximum area shrinkage-cracking ratio is recommended as an accurate and reliable parameter in the identification and classification of expansive soils.</p>