TeX is a typesetting system invented by the famous computer scientist Donald E. Knuth (Gartner). Using TeX, you can easily generate and print high-quality dvi files. Use dvips, dvipdmx, pdflatex and other programs to generate pdf, ps, file and LaTeX2html to generate html files. It is very popular in academic circles, especially in mathematics, physics and computer science. TeX is generally regarded as a good typesetting tool, especially when dealing with complex mathematical formulas. Using terminal software such as LaTeX, TeX can typeset beautiful words. Macro package on CTAN can expand functions, make slides and define templates. Chinese support can be completed through CCT, CJK, etc. TeX provides a powerful and flexible typesetting language with more than 900 instructions, and TeX has macro function, so users can constantly define their own new commands to expand the functions of TeX system. Many people use the macro definition function provided by TeX to redevelop TeX, among which AMS-TeX recommended by American Mathematical Society is very suitable for mathematicians, and LaTeX system is suitable for general articles, reports and books. TeX system is recognized as the system with the best mathematical formula. The American Mathematical Society (AMS) encourages mathematicians to use the Tex system to contribute to their journals. Many first-class publishing houses in the world, such as Kluwer, Addison-Wesley, Oxford University Press, etc. , and also publish books and periodicals with TeX system. Most TeX systems are free. Professor Knuth also made public all his source programs. TeX system has been implemented on hundreds of computer systems. The typesetting result DVI (Device Independent) file of TeX system has nothing to do with the output device. DVI files can be displayed, printed and typeset, and can be output on almost all output devices. TeX typesetting source files and results are compatible with each other on various computer systems.