1. Classified by mixing ratio Foam extinguishing agent can be divided into 1.5%, 3%, 6% and so on according to the proportion of foam liquid mixed with water. 2. According to the expansion ratio classification Foam extinguishing agents according to their foaming times can be divided into low multiple foam, multiple foam and high multiple foam three categories. Low expansion foam foam multiplier times generally less than 20 times, the middle multiples foam foam multiples of 20 to 200 times, high-fold foam extinguishing agent, the expansion ratio is generally between 200 to 1000 times. 3. Classified by usage characteristics Foam extinguishing agents according to their use of places and characteristics can be divided into Class A foam fire extinguishing agents and Class B foam fire extinguishing agents, Class B foam fire extinguishing agents can be divided into water-insoluble foam fire extinguishing agents (such as protein foam fire extinguishing agents, Agent, "light water" foam fire extinguishing agent) and an alcohol-resistant foam fire extinguishing agent (gel-type anti-soluble foam fire extinguishing agent). 4. According to the matrix of synthetic foam classification Foam extinguishing agents can be divided into protein foam and synthetic foam fire extinguishing agent. Protein type foam fire extinguishing agents include common protein foam fire extinguishing agents, fluorine protein foam fire extinguishing agents, film-forming fluorine protein foam fire extinguishing agents, anti-solvent and film-forming protein anti-solvent foam fire extinguishing agents; synthetic foam fire extinguishing agents are mainly high-fold foam fire extinguishing agents , High, medium and low times general foam fire extinguishing agent, water film foam fire extinguishing agent, anti-water-soluble film-forming fire extinguishing agent, Class A fire foam.