Microscope is a precision optical instrument. Its core technology is optical technology. The quality of the product is high. The key is to look at the optical system (including lighting system, objective lens, etc.), which is the basic principle of purchasing a microscope. In the imported microscope manufacturers (Germany Zeiss, Germany Leica, Japan Nikon, Japan Olympus) the quality is mixed, the user should be rational analysis in the selection process, do not go astray, and ultimately cause inevitable economic losses.