Abstract: Objective To study the potential effect of hypoxia on invasion and metastasis of leukemia cell line Raji. Methods Raji cells were cultured with normal method in vitro and treated with 1%，3%，5% oxygen for 24h, the normoxic cultured group was used as control. Then cell adhesion assay，cell migration assay and cell invasion assay were used to observe the effects of oxygen on adhesion, migration and invasion ability of Raji cells, and RT-PCR was used to evaluate the mRNA expression levels of HIF-1α, VEGF, MMP-2 and MMP-9. The protein level of HIF-1α was observed by Western Blot. Results Compared with control group, 3%，5% oxygen groups could significantly enhanced the adhesion，migration and invasion of Raji cells (P<0.01 or P<0.05)，and could also up-regulate the protein level of HIF-1α and the mRNA level of HIF-1α，VEGF and MMP-9，but the mRNA level of MMP-2 was not obviously expression. However， all indexes of 1% oxygen group merely changed when compared with control group (P>0.05). Conclusion Moderate hypoxia could enhance the ability of invasion and metastasis of Raji cells. The possible mechanism is HIF-1α up-regulate the expression levels of VEGF and MMP-9.