One’s HS class grades/HS class ranking usually has no bearing on college admissions in China.
Instead, one’s choice of college and major are solely determined by how well one scored on the national college entrance exam.
However, the exam is much more closely tied to the curriculum* at academic-track HS in China and other East Asian countries with this system so if one slacks on one’s HS classes, one is unlikely to do well on the national college entrance exam. Especially given the keen competition to vie for the highly desirable top universities and top majors.**.
- Depending on whether one chooses the arts/social sciences/humanities track or the STEM track in academic HS/exam.
** In my parents’ generation in the '50s, it was much harder to gain admission as an English language and lit major than Law, Business/Commerce, or especially Chinese language and lit at a given university in the ROC(Taiwan) due to the far greater popularity and better job prospects of the former over the latter majors in that period.