Abstract: Objective : To investigate the possible correlation between osteoglycin expression and matrix metallopro-teinase (MMP) activity in tumor cells. Methods : A eukaryotic expression plasmid pIRESpuro3 osteoglycin (+)was constructed and transfected into mouse hepatocarcinoma Hca-F cells with high metastatic potential. In vi-vo tumor metastasis assay was employed to evaluate the contribution of osteoglycin expression to the malig-nant behavior of Hca-F and zymographic analysis was used to observe the possible correlation between os-teoglycin expression and MMP activity of Hca-F cells cultured with different condition. Results : Hca-F cellstransfected with pIRESpuro3 osteoglycin (+) produced effective and stable expression of osteoglycin at mR-NA and protein levels. Lymphatic metastasis rate was decreased in tumor burden mice (P=0.028). High ex-pression of osteoglycin decreased MMPs activity of Hca-F cells cultured with extract of lymph node (P<0.05 or P<0.01) but didn't influence MMPs activity of Hca-F cells cultured with liver or spleen extract or DMEMmedium. Conclusion : High expression of osteoglycin can decrease MMPs activity in Hca-F cells cultured withextract of lymph node. Regulation of MMPs activity might be one of the mechanisms that osteoglycin can sup-press lymphatic metastasis.