Inverted metallographic microscope MHML-20/MHML-20BD adopts excellent infinity optical system and modular functional design concept, which can easily upgrade the system and realize polarized light observation, dark field observation and other functions. Compact and stable high rigidity body fully embodies the anti-vibration requirements of microscope operation. The ideal design meets the requirements of ergonomics, which makes the operation more convenient and comfortable and the space wider. It is suitable for microscopic observation of metallographic structure and surface morphology, and is an ideal instrument for research on metallography, mineralogy and precision engineering.