Two different 'cutoff' numbers get quoted after the gaokao and they mean different things. Confusing them will lose you an application cycle.
The 批次线 (batch cutoff) is set by your province and determines which tier of universities (一本 / 二本 / 专科) you can apply to at all. Below the batch cutoff, that whole tier is closed to you regardless of specific-school interest.
The 投档线 (school cutoff) is set retroactively for each university and major, based on the lowest score of admitted students that year. This is the one you actually need to beat to get into a specific place.
Historical 投档线 for the past three years is your best signal. Universities publish these. A gap between your score and the historical cutoff of about 10-20 points is a healthy target-school margin.
Regional differences are enormous. A score that is 一本 in one province is 二本 in another. Never compare your score to a national average.