In order to understand the impact of the explosive propagation of aeolosoma hemprichi on the performance of an activated sludge-biofilm reactor at various temperature conditions, we conducted a beaker experiment and simulated the activated sludge-biofilm reactor, which is operated in a 1.0 L reactor with the filler dosing rate of 30% at 20ºC, 25ºC, and 30ºC. We inoculate aeolosoma hemprichi after the activated sludgebiofilm reactor became steady, investigated whether and when the explosive propagation of aeolosoma hemprichi occurs at various ambient temperatures, and examined its impact on the performance of the activated sludge-biofilm reactor. The results show that the removal rate of ammonia nitrogen is basically stable at between 90-95%, and that of total nitrogen has remained at around 45% at 20ºC. When the filler dosage rate is 30%, the removal rate of COD is stable between 85%-90%. The population density of aeolosoma hemprichi basically kept at 10 ind./mL, indicating that the aeolosoma hemprichi did not produce explosive reproduction. The explosive propagation of aeolosoma hemprichi occurs at the temperature of both 25ºC and 30ºC, while the maximum population densities of aeolosoma hemprichi are 383 ind./mL and 200 ind./mL, respectively. In addition, the explosive propagation has no impact on the removal rates of inlet and outlet COD and NH₃-N, but it leads to an increase in the release rate of TN. Moreover, it is certified that the explosive propagation of aeolosoma hemprichi does not have an impact on the loss of biofilm. Finally, after multivariate regression analysis with SPSS, we concluded that the maximum population density of aeolosoma hemprichi has a significant correlation with the release rate of TN.