Abstract: This study was designed to evaluate the inhibition effect of λ-carrageenan oligosaccharides on neovascularization In vitro by chick chorioallantoic membrane (CAM) model and human umbilical vein endothelial cell (HUVEC). λ-Carrageenan oligosaccharides caused a dose-dependent decrease of the vascular density of CAM, and adversely affected capillary plexus formation. At a high concentration of 1 mg·mL^-1, this compound inhibited the endothelial cell proliferation, while low concentration of λ-carrageenan oligosaccharides (<250 μg·mL^-1) affected the cell survival slightly (>95%). Different cytotoxic sensitivity of λ-carrageenan oligosaccharides in three kinds of cells was observed, of which HUVEC is the most sensitive to this oligosaccharides. The inhibitory action of λ-carrageenan oligosaccharides on the endothelial cell invasion and migration was also observed at relatively low concentration (150-300 μg·mL^-1) through down-regulation of intracellular matrix metalloproteinases-2 (MMP-2) expression on endothelial cells. Current observations demonstrated that λ-carrageenan oligosaccharides are potential angiogenesis inhibitor with combined effects of inhibiting invasion, migration and proliferation.