Disclosed in the present invention are organic-inorganic hybrid particles, and a preparation method therefor and applications thereof in the modification of cement-based materials. The organic-inorganic hybrid particles of the present invention consist of organic components and inorganic components, and the inorganic components and the organic components are mutually connected in a crossed manner by means of covalent bonds instead of core-housing structures. The inorganic components and the organic components are connected by means of covalent bonds. In the organic-inorganic hybrid particles of the present invention, the organic components are used for improvement of mechanical properties of the cement-based materials; by complete connection of the organic components with CSH particles by means of the inorganic components and the covalent bonds, toughness efficacy of the organic components is improved; in addition, as more organic-inorganic hybrid particles are doped into the cement-based materials, the mechanical properties of the cement-based materials are more evidently improved.