The membrane filtration method is one of the testing methods for sterility and microbial limit testing included in the appendix of the 2000 edition of the Pharmacopoeia of the People's Republic of China. In recent years, it has been increasingly widely used in drug inspection, with the characteristics of simplicity, speed, and accuracy. This method can quickly collect bacteria in aseptic testing; In the microbial limit test of drugs, the antibacterial effect of certain components in the drug can be removed; It can be used as one of the experimental methods in the validation of drug microbiological examination methods and the validation of microbial recovery from drug formulations. This method is also applicable for sterile testing of packaging materials for biological products and pharmaceuticals. The 2005 edition of the Pharmacopoeia of the People's Republic of China specifically stated that this law should be given priority for adoption.