Theoretical physics is a postgraduate course. At present, there is no school offering theoretical physics (there are physics and physics bases nearby, but not pure theoretical physics), so there is no special undergraduate teaching material for theoretical physics. There are several concise courses, among which the fundamentals of theoretical physics (Peng Huanwu \ Peking University Press, 2005) and the fundamentals of theoretical physics (Liu Lianshou \ \/Higher Education Press) should be better. The theoretical physics foundation is systematic and concise. It's best to study general physics and four mechanics first, because many proofs are omitted, but the exercises at the back of the book basically have answers. The book Basic Course of Theoretical Physics is relatively thick, with more than 700 pages. The book is full of content, detailed explanation, many examples and clear system. \ r \ There are many postgraduate courses. Many universities have theoretical physics textbooks, as well as translations of foreign textbooks, such as Landau's Course of Theoretical Physics (Higher Education Press, 2008) (this should be difficult to understand). Go and have a look if you are interested. \ r \ But personally, I feel that the undergraduate stage mainly focuses on general physics and specialized courses in the undergraduate stage, which are necessary foundations and can deepen our understanding of physical phenomena and physical essence. Just looking at some basic courses and concise courses will help to clarify the context, but you don't have to look at the textbooks of theoretical physics, and the mathematical tools are more advanced. \ r \ nIf you want to take the entrance examination for theoretical physics, you can refer to the undergraduate courses offered by physics departments of domestic universities first. Basically, there are four courses: mechanics (electrodynamics, thermodynamics and unified mechanics, theoretical mechanics and quantum mechanics) and mathematical physics methods. In mathematics, there are advanced mathematics and linear algebra, both of which need to be learned. Different schools also have some different courses, such as digital and analog circuits, but these are more inclined to engineering. If you want to engage in theoretical physics, you must lay a good foundation in mathematics and study the four mechanics relatively deeply, which will benefit a lot.