A pressure relief structure of a flash explosion device comprises spray explosion machines and raw material bins connected with the spray explosion machines, and is characterized in that the number of the spray explosion machines is two, and the spray explosion machines include the first spray explosion machine and the second spray explosion machine; the two raw material bins are connected to the first spray explosion machine and comprise the first raw material bin and the second raw material bin, and two raw material bins are connected to the second spray explosion machine and include the third raw material bin and the fourth raw material bin; and each raw material bin is correspondingly provided with a gas collection bin in a communicated manner, and the gas collection bins are connected in a paired manner. When the multiple spray explosion machines alternatively work, waste gas can be exhausted to the gas collection bins at the same time; and the gas releasing space is increased, so that the gas exhaust pressure intensity is reduced, and the gas flow speed of the waste gas is reduced. A tail gas treatment device can carry out purification treatment on the waste gas, and the pollution of the waste gas to the environment is reduced. Through the manner that the gas collection bins of the different spray explosion machine are communicated, the utilization rate of space inside a garbage treatment workshop is improved, and existing equipment and an existing workshop are transformed.