The recirculation fumigation system is composed of an application device, a recirculation device and a detector. It is a system with great functions, high safety and good insecticidal effect, which is manufactured based on the grain storage theory, the air aerodynamic recirculation theory, the chemical control theory and the microcomputer control technology in strict line with GB/T17913-1999. It has advantages including less chemical consumption, even gas distribution, low control cost, high personal safety, apparent environmental protection benefits, high automation, simple operation, etc.