[Objectives]  To investigate the effects of different soil moisture levels and duration of flooding on the emergence and reproduction of Spodoptera frugiperda, and thereby determine if these factors affect the occurrence of this pest. 【Methods】 S. frugiperda were randomly assigned to different soil moisture and duration of flooding treatment groups in a laboratory.【Results】 The highest eclosion rate (100.00%) was recorded at relative soil moisture levels of 30% and 40%. The eclosion rate reached 93.33% at a relative soil moisture of 50%-90%, which was significantly higher than that at soil moisture levels of 0, 10% and 100% (26.67%-73.33%). However, relative soil moisture had no significant effect on the average number of eggs laid. There was no significant difference in the emergence rate when soil had been soaked for 1-4 days before larvae entered it. However, soil flooding significantly affected the emergence rate of pupae, which decreased significantly with the duration of flooding; no adults were observed after soil had been flooded for 4 days. Direct flooding affected the emergence rate of both mature larvae and pupae. The emergence rate of larvae continued to decrease with the duration of flooding, and mature larvae did not emerge after 10h of flooding. The emergence rate of pupae was 69.70% less than that of the control group after 10h of flooding. 【Conclusion】  Excessive accumulated water significantly inhibits the emergence of S. frugiperda. This information can be combined with weather and rainfall data to predict the population dynamics of S. frugiperda, and used to adjust soil water levels to control adult emergence.