This study aimed to evaluate the impact of Intermittent Hypoxia (IH) on neuronal activity and apoptosis in embryonic rat cortical neurons in vitro. The cultured cortical neurons were randomly divided into four experimental groups: IH group, Intermittent Normal Oxygen group (INO), Persistent Hypoxia group (PH), and Controls (CON). The IH group was further divided into five subgroups according to the degree and time points of hypoxia. Using the MTT cell proliferation assay and 4?, 6-diamidino-2- phenylindole staining to evaluate neuronal cell proliferation and apoptosis, we observed significant differences between the different IH subgroups and the PH group (P<0.01). No significant difference was found among the IH subgroups (P>0.05). Under the same hypoxia degree and accumulative time, intermittent oxygen supply exhibited a higher impact on neuronal activities and apoptosis than sustained oxygen supply. Thus, IH could cause significant changes of neuronal activities and apoptosis.