I’m wondering that what major can I choose in university for becoming a doctor. And I look up online, there is a program called pre-med. Are there any requirements to be a pre-med student? Also, what classes can I take in high school to be better prepare for the medical classes in the future?
Any major. I had a friend that was an economics major. There are required class to get into medical schools. Nothing outside of a rigorous schedule to prepare in HS. Also, be aware, a very very small percentage of HS students that say they want to go to medical school actually do enroll.
Pre-med does not require any specific undergraduate major. About half of applicants and matriculants to medical school are biology majors. Biology conveniently covers most pre-med course requirements, but those who do not get into medical or other professional school can find the biology job market difficult. Pre-meds in other majors take the non-overlapping pre-med course requirements in their breadth elective or free elective space in their schedules. Some majors (e.g. engineering other than bioengineering or chemical engineering) may have voluminous non-overlapping requirements that make it difficult to fit the pre-med courses into the schedule.
A pre-med should choose a major that s/he is strong in, because college GPA will be an important factor (along with MCAT score) that medical schools use to initially weed applications down to a manageable number (science GPA in college will also be looked at in addition to overall GPA). Only about half of pre-meds who apply to MD medical schools in the US are admitted to any medical school. But many more frosh pre-meds do not apply after seeing that their GPA and/or MCAT score are too low for it to be worth the effort and cost.
As a high school student, it is best to take all three of the main sciences (biology, chemistry, and physics) as well as math through precalculus at least (calculus preferred if available to you). Statistics may be a helpful elective (but in addition to precalculus and calculus, not in place of precalculus and calculus). AP computer science principles may also help, because computers are used everywhere. Of course, strength in English and other subjects is helpful as well. Knowledge of a foreign language commonly spoken in regions you may want to practice medicine can also help.