To investigate the expression of cyclin G1, cyclin G2 in nasopharyngeal carcinoma (NPC) cell lines and its significance. The protein expression of cyclin G1, cyclin G2 in NPC cell lines of different differentiation degree (HNE2, CNE1) was detected by indirect immunofluorescence. The mRNA expression of cyclin G1, cyclin G2 in HNE2 and CNE1 was measured with RT-PCR. The cyclin G1 expression in HNE2 and CNE1 was weak, and cyclin G2 expression in the cytoplasm near cell membrane was strong, continuous, and homogeneous. The expression level of cyclin G1-mRNA in HNE2 was 2.097 ± 0.262, which was significantly higher than CNE1 (0.997 ± 0.286, P < 0.05); the expression level of cyclin G2-mRNA in HNE2 was 0.708 ± 0.107, which was significantly lower than CNE1 (1.216 ± 0.037, P < 0.05). Abnormal expression of cyclin G was closely related to tumor differentiation, the origin, and progression of NPC.