The secondary A2 type biosafety cabinet is widely used in medical and health, food safety, biopharmaceutical and other fields. Its main function is to protect experimenters handling infectious experimental materials such as primary cultures, strains of bacteria and diagnostic specimens, and avoid the harm caused by infectious aerosols or spillages that may be produced during the operation. It can also protect the laboratory environment and experimental samples. It is an indispensable safety protection equipment in the laboratory. It is classified as three types of medical devices in the medical device classification catalogue.