Under the opportunity of high-quality opening-up, the importance of income equity for residents is becoming increasingly prominent. Based on CHNS micro database, the paper systematically investigates the scale effect and quality effect of opening-up represented by foreign direct investment (FDI) on residents' intergenerational income mobility and its mechanism. The study concludes that: (1) The scale effect and quality effect of FDI inflow can significantly improve the intergenerational income mobility level, which achieves inclusive income growth to a certain extent. (2) The scale of FDI can increase the possibility of non-agricultural employment and the quality of FDI can increase the possibility of workers’ employment and informal employment. (3) As far as the mechanism is concerned, the active infl ows of FDI improve the intergenerational income mobility by changing the nature of employment (non-agricultural employment). Rising FDI quality improve the intergenerational income mobility by increasing informal employment and employment type of worker. (4) The heterogeneity analysis shows that the scale and quality effects of FDI in the eastern and urban regions signifi cantly enhance the intergenerational income mobility level compared with that in western and rural regions, which may be more conducive to income equity. Therefore, the government should continue to promote the comprehensive construction of high-quality opening-up capacity and quality, optimize the regional allocation of employment resources, and enhance the diversity of employment forms and modes.