The invention discloses a method for determining whether normal operation of an anaerobic sewage treatment system is affected by chemical reagents for production or not, and an anaerobic reaction device. The anaerobic reaction device comprises an anaerobic reaction container, an oscillator, a gas collection container and a loading container, wherein the anaerobic reaction container is arranged on the oscillator; the gas collection container and the loading container are both filled with a liquid; the gas collection container is arranged in the loading container in a state that the opening faces downwards; the gas collection container is in a liquid sealing state at the moment; the anaerobic reaction container and the gas collection container are communicated through a pipeline. The method comprises the following steps: simulating an anaerobic environment, feeding an identical anaerobic sludge amount and a sewage quality amount into the anaerobic reaction device, adding chemical reagents (and preparing blank groups) of equal production discharge concentration in an external environment, testing, comparing the CODcr removal rates and the gas yield with those of the blank groups, and thereby determining whether the chemical reagents have toxicity for anaerobic bacteria or not.