In response to China’s new “people-oriented urbanization” strategy, investigating the current integration situation of rural-to-urban migrants (RUMs) in cities is essential. However, existing studies have not focused on their subjective willingness and adaptive capacity. Moreover, the mechanism of RUMs’ urban integration has not been fully explored.

The conceptual framework of vulnerability, which originated from the discipline of natural hazards, is perfectly constructive to address these drawbacks. It consists of three main components, including exposure, sensitivity, and adaptive capacity. Vulnerability index has been constructed and calculated by combining the analytic hierarchy process (AHP) and Delphi method. The spatial pattern of vulnerability level is also analyzed with geographic information system (GIS). Furthermore, the underlying mechanism of vulnerability and its associated factors are investigated with the principle component regression.

Three major conclusions are reached. First, the vulnerability level of the RUMs to social exclusion presents a heterogeneous pattern between inland and coastal cities in Shandong Province. Second, while the exposure and sensitivity level of each city correlate spatially with the vulnerability level, RUMs’ adaptive capacity further moderates it. Lastly, the level of urban development is revealed to be a key factor influencing vulnerability. This study offers meaningful references to promote inclusive urbanization and sustainable urban development.