Abstract: Abstract: Food waste is an excellent raw material for anaerobic fermentation, due to its rich in starch, protein, and high content of organic matter. But there are relatively high concentrations of salt and oil difficult to remove, particularly on a high removal cost in anaerobic fermentation. This study aims to explore the effects of high salt and oil in eat hutch garbage on the acid production and related enzyme activities of anaerobic fermentation. Taking food waste as the raw material in fermentation, a batch anaerobic fermentation test was carried out under the conditions of inoculation content of 30%, the Total Solid (TS) of 8%, the temperature of 35℃, and the initial pH of 7. A minimal inhibitory concentration test was selected to determine the high concentration in salt and oil. Initial raw materials were divided into six test groups for anaerobic fermentation according to the maximum concentration and gradient of salt and oil, including 5, 7, 9, 11, 13, 16 g/L. A detection was performed on the Soluble Chemical Oxygen Demand (SCOD) in biogas slurry, to determine the type and content of Volatile Fatty Acids (VFAs), as well as activity change of amylase, protease, coenzyme F420, and dehydrogenase. The experimental results are as follows. The SCOD did not change, but the peak SCOD decreased by 23%-38% with a 2-3 d delay, indicating a more intense inhibition phenomenon with the increase of salt/oil concentration. The high salt/oil content delayed the occurrence time for the peak of VFAs, leading to the accumulation of VFAs. The accumulation peak of VFAs decreased first and then increased with the increase of the salt/oil content, where the accumulation concentration of VFAs decreased by 34.76%. Moreover, the decomposition of oil-produced VFAs contributed to the increase in the concentration peak of VFAs. Butyric acid (accounting for 54%-75%) was the main acid product under the condition of high salt/oil. There were similar contents (about 10%-20%) of propionic acid, acetic acid, and isovaleric acid. The lowest contents were only 1%-8% of n-hexanoic acid, isobutyric acid, and n-valeric acid. There were few different proportions of VFAS components under various conditions of high salt/oil. The peak values decreased by 5%-35%, 7%-17%, 8%-27%, 5%-26% for the activity of amylase, protease, coenzyme F420, and dehydrogenase, respectively. Furthermore, the peak value of related enzyme activity all appeared 3-6 d later. There was more obvious inhibition of enzyme activity as the concentration of salt/oil increased. Therefore, the high salt/oil inhibited the dissolution of organic matter in anaerobic fermentation, further inhibiting the activities of hydrolase and methanase as a result of the accumulation of VFAs. This finding can provide a promising theoretical basis for the effect of high salt/oil on anaerobic fermentation.