This paper constructs an analytical framework of trade openness affecting intergenerational income mobility, explores the mechanism of trade openness affecting intergenerational income mobility, and proposes relevant theoretical hypotheses of trade openness affecting intergenerational income mobility, which are tested empirically using CHNS data in 2011 and 2015. The empirical tests are basically consistent with the theoretical hypotheses: (1) trade openness helps to promote intergenerational income mobility, which can make children’s income climb to levels higher than their parents’income and prevent children’s income from flowing to levels lower than their parents’income, and in addition, it is found that high level of foreign openness has a greater effect on promoting intergenerational income mobility; (2) the impact of trade opening on intergenerational income mobility is heterogeneous in terms of urban-rural, regional, paternal income level and paternal education; (3) trade opening can bring intergenerational income mobility by promoting intergenerational education mobility and industrial structure upgrading. Based on the above conclusions, China should continue to promote a high level of openness to the outside world, narrow the gap between the rich and the poor in urban and rural areas, promote equity in education and upgrade the industrial structure, and contribute to equality of opportunity, so as to achieve common prosperity.