The disparities in the quality of senior secondary education opportunities are one of key topics in educational equity research in China as they have a critical impact on students' access to higher education and even their future occupational attainments. Students' senior secondary education opportunities are related to multiple factors. This study attempted to examine the relationship between family capital and the quality of children's senior secondary education opportunities. The research into the post-junior secondary education tracking in County B of Jiangsu Province demonstrated that compared with vocational secondary education opportunities, children's access to general senior secondary education (including ordinary and key high schools) was significantly and positively affected by family social capital and less so by family cultural capital, but had a weak correlation with family economic capital; and that cultural capital had more significant impact on children's admission to high-quality senior secondary schools than to ordinary high schools. Subjective aspects of family capital helped improve the access to ordinary senior secondary education of children from underprivileged classes, whilst objective aspects of family capital could limit their key high school enrollment opportunity. It was suggested that the government push through the implementation of the "quota allocation policy" to promote balanced distribution of high achieving students; and that disadvantaged families make more efforts to increase their cultural capital, and schools and communities provide more support to disadvantaged groups to compensate for their paucity of cultural capital and to upgrade the quality of senior secondary education opportunities of their children.