〔Abstract〕 Objective To explore the effects of an ultradian light cycle on the periodic expression of glutamate receptors in the suprachiasmatic nucleus and the lateral habenula nucleus. Methods An ultradian light cycle T7(3.5 hours/3.5 hours light: dark) was used to establish an ultradian light cycle model group and T24(12 hours/12 hours light: dark) was used to establish control group. The expression of key proteins in the brain regions of the suprachiasmatic nucleus(SCN) and the lateral habenula(LHB) of the hypothalamus were analyzed by Western blot. Including glutaminergic receptors, pituitary adenylate cyclase activating polypeptide(PACAP) receptors, and downstream signaling molecules. Results Western blot results showed that the expression of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor subunit 2(GluR2) in SCN under Zeitgeber time(ZT) 1 and ZT 5 increased under an ultradian light cycle compared with normal photoperiod(P<0.05,P<0.01), the overall expression of GluR2 in T7 group was higher than that in T24 group(P<0.01), the overall expression of GluR2 in LHB group T7 was lower than that in T24 group(P<0.01). Compared with T24 photoperiod, the overall expression of N-methyl-D-aspartic acid receptor subunit 2(NR2B) in SCN increased under T7 photoperiod(P<0.05), the overall expression of phosphorylation of extracellular signal-related kinase(P-ERK) in LHB significantly increased under T7 photoperiod(P<0.05). Conclusion An ultradian light cycle would cause an up-regulating of GluR2 and NR2B expression, a down-regulating of GluR2 expression and up-regulating P-ERK expression in LHB.