How does the threshold for urban household registration in China affect the willingness of rural to urban migrant population to settle down?

China has a large floating population, a key group for promoting basic public service equalization. This study examines how urban household registration thresholds affect rural-urban migrants’ willingness to settle. Findings show two key impacts: a high threshold significantly crowds out settlement willingness by making urban citizenship unaffordable, with high-skilled, housingless migrants being more sensitive. From an urban scale perspective, increased thresholds have a crowding-out effect in Type I large cities, mega cities, and super large cities, with mega cities showing the strongest effect—expanding urban populations reduce migrants’ welfare, prompting them to seek opportunities elsewhere. This study clarifies the threshold’s impact mechanism, offering support for urban development.