Examining the change of rural settlement land scale and its influencing factors is of great theoretical and practical significance for optimizing the spatial pattern of rural settlements and implementing the national strategy of rural revitalization. In this study, the spatial distribution and scale of rural settlement land in the Loess Plateau between 1990 and 2015 were examined using the rank-size analysis, kernel density analysis, and geographical detector and the ArcGIS10.2 software. The influencing factors and driving mechanism of rural settlement land scale pattern are revealed. The results show that: (1) Since 1990, the number of rural settlement patches and the scale of land use in the Loess Plateau have shown an overall increasing trend, of which the number of rural settlement patches increased most obviously from 2000 to 2005, and the scale of land use expanded most obviously from 2005 to 2010. (2) The scale of rural settlements in the Loess Plateau is in a stage of unbalanced development, and the spatial distribution of rural settlements shows clear historical inheritance, which is manifested in overall expansion and local filling. (3) The formation of rural settlement land scale pattern in the Loess Plateau is affected by multiple factors. Topographic relief, annual average temperature, and annual average precipitation are the main natural forces, and per capita grain output, total population, and the proportion of rural population are the key human driving forces. The influence of any combination of two factors on the regional difference of rural settlement land scale is stronger than that of a single factor. (4) The interaction of various factors has significant influence on the scale pattern of rural settlement in the Loess Plateau. The interaction of natural geographical factors and socioeconomic factors has the most extensive influence on the scale pattern of rural settlement land in the gully region, the rocky mountain area, and the aeolian sand area of the Loess Plateau. The interaction between socioeconomic factors has obvious synergistic effect on the scale pattern of rural settlement land in the hilly and gully areas of the Loess Plateau and in valley plain areas. Grain production and location have an obvious synergistic effect on the scale pattern of rural settlement land in the irrigation agricultural areas.