The invention provides oligosaccharide components with anti-platelet aggregation activity, and a preparation method thereof. According to the invention, the components are obtained by further separation and refining of a raw material which is a Shuxuetong injection (a traditional Chinese medicine injection extracted and refined from leech and lumbricus). The oligosaccharide components are mainly a series of oligosaccharide components formed by polymerization of approximately 2-10 monosaccharide units. The molecular weights of the oligosaccharide components range from 200Da to 3000Da. The oligosaccharide components have significant inhibition effects against ADP-induced and collagen-induced platelet aggregation. With the technical scheme provided by the invention, the obtained oligosaccharide components with potential anti-platelet aggregation activity have moderate molecular weights. The oligosaccharide components can also be used as potential precursor substances for further developing anti-platelet therapy drugs applied in the field of cardiovascular and cerebrovascular diseases by improving the activity of the oligosaccharide components through chemical modification or transformation.