NaOH and NaClO are the common chemicals used for in-situ cleaning in anaerobic membrane bioreactors (AnMBRs); however, the cleaning reagents can affect the viability of anaerobic microbes along with the elimination of membrane foulants. In this study, the methanogenic activities and related enzymes of anaerobic sludge were tested under the short-term exposure to NaOH (10~400mg/L) and NaClO (5~40mg/L), including specific methanogenic activity (SMA), biochemical methane potential (BMP), dehydrogenase activity (DHA) and coenzyme F₄₂₀ activity. The results showed that SMA decreased with the increase of NaOH concentration. The NaOH concentrations of 0~200mg/L caused inhibition effects while the concentrations above 200mg/L might induce cell death. In terms of key enzymes, dehydrogenase could tolerate relatively high NaOH concentrations while coenzyme F₄₂₀ was more sensitive to NaOH. The activities of coenzyme F₄₂₀ were slightly improved at the NaOH concentration of 10~100mg/L and declined when NaOH concentration was above 100mg/L. Under the exposure of NaClO, SMA decreased from 50mLCH₄/(gVSS·d) to 15mL CH₄/(gVSS·d) when NaOCl concentration increased from 0 to 40mg/L while BMP exhibited no obvious change. The activity of DHA and coenzyme F₄₂₀ decreased with the increase of NaClO, and DHA decreased by 30% and activity of coenzyme F₄₂₀ decreased by 70% at the NaClO concentration of 40mg/L.