Electromagnetic field and electromagnetic wave are theoretical knowledge about electromagnetism. Around the origin and application of Maxwell equations, it generally includes electrostatic field, steady current field, constant magnetic field, time-varying electromagnetic field, plane wave, waveguide foundation, antenna foundation and so on. From simple to complex, from static to time-varying, from electric field and magnetic field to electromagnetic field, from theory to application, the origin, development and application of electromagnetic field theory are expounded in depth, which is the basis for subsequent research on microwave and antenna theory. Electromagnetism in college physics is a superficial explanation of electromagnetism, which is also based on Maxwell equations, but it is far less systematic, detailed, comprehensive and profound than the former. Compared with electromagnetic fields and electromagnetic waves, the electromagnetic part of college physics focuses on the introduction of concepts and explains the origin of Maxwell equations to beginners, without involving specific applications. Although field theory is introduced into the analysis method, algebra is still the main method, while electromagnetic field and electromagnetic wave analyze the problem purely from the perspective of field theory. (Bibliography: Feng Enxin's Electromagnetic Field and Electromagnetic Wave, Wu Baishi's College Physics, xidian university Lecture Notes) qijun00 1