Abstract: In order to investigate the action mechanism of the different sources microbial inocula during the composting process, and further provide theoretical support for the screening and application of compost microbial inoculant. The endogenous inocula (M37) and exogenous inocula (VT) were as compost Inoculants, studied the effects of indigenous and exogenous inoculation on changes of temperature, oxygen concentration, as well as protease activity, urease activity, dehydrogenase activity and cellulase activity during composting stages in a composting bioreactor. The results showed that, at the beginning of composting, endogenous inocula were beneficial to rapid rising temperature and the cumulation of protease activities and urease activities. At the high-temperature period, exogenous inocula were beneficial to maintain a higher temperature and enhanced dehydrogenase activities and cellulase activities. At the warming and high-temperature period, there was very significant negative correlation between temperature and oxygen concentration. During the period of raising temperature, the protease activity, urease activity and temperature were highly significant positive correlation (P<0.01). At the period of raising temperature and high-temperature, dehydrogenase activity and temperature were all highly significant positive correlation between (P<0.01). There was a significant positive correlation between the temperature and cellulase activity at the high-temperature period (P<0.01).