My hukou is from Hainan, so I went to high school in Guangdong and then went back to Hainan for the college entrance examination, okay?

This is possible. I remember when I was in high school, one of my classmates was a local, but both my ID card and household registration book were from other provinces. As a result, he didn't take the local exam in the college entrance examination, but took his ID card to that province to take the college entrance examination, because the score in that province was lower.

But you must have someone who can help you solve this problem.

In fact, you can also take the college entrance examination in different places or in Guangdong, but I think you should first find out which province in Guangdong and Hainan has the lowest score, and choose the one with the lowest score to omit the college entrance examination, because it is better to get into your favorite university.

I hope I can help you.