According to the composition of the different media for bacterial culture. It can be divided into synthetic media, natural media and semi synthetic media.
（1）Synthetic media. The components of the synthetic media are all known chemicals. The chemical composition of this media is clear, the composition is accurate, the repeatability is strong, but the price is expensive, and the growth of microorganisms in this media is slow. Such as Gao's No.1 synthetic media and Chashi（Czapek) media, etc.
（2）Natural media. It is made of natural substances, such as steamed potato and common beef soup. The former is used to cultivate mold and the latter is used to cultivate bacteria. The chemical composition of this kind of culture media is very unsteady and difficult to determine, but it is easy to prepare, rich in nutrition and good in culture effect, so it is often used.
（3）Semisynthetic media. On the basis of natural organic matter, some inorganic salts of known ingredients or some natural ingredients, such as potato glucose agar media for mould culture, should be added properly. This kind of media can more effectively meet the needs of microorganisms for nutrients.