With social support theory as the basis, this study looks into public library resources and information support type for migrant workers, as well as informative, instrumental, social and emotional support content. Then the study analyzes in two dimensions the influencing factors that restricts migrant workers using public library. The latter part of the paper discusses some valuable topics: the role and position of public library in the migrant workers' social supporting system; the availability, accessibility, equalization and characteristics of public library's service and resources; and how to avoid labeling "migrant worker".