It is still difficult to apply for undergraduate mathematics in the UK. To give a few examples, to choose Imperial College London in London, you must first have a background related to mathematics, such as studying applied mathematics, engineering or physics. Secondly, it depends on the background of undergraduate colleges, that is to say, if you want to study mathematics as a graduate student, it depends on which undergraduate school you graduated from in China. The IELTS score should meet the requirements, generally 6.5. Different schools have different application details. But basically all of them need to have a subject background, and some schools need to have corresponding programming experience.
/zd/lx